* kernel BUG at security/keys/keyring.c:LINE! @ 2018-10-05 11:16 syzbot 2018-11-02 23:15 ` [PATCH] KEYS: always initialize keyring_index_key::desc_len Eric Biggers 2018-11-03 1:58 ` [PATCH v2] " Eric Biggers 0 siblings, 2 replies; 9+ messages in thread From: syzbot @ 2018-10-05 11:16 UTC (permalink / raw) To: dhowells, jmorris, keyrings, linux-kernel, linux-security-module, serge, syzkaller-bugs Hello, syzbot found the following crash on: HEAD commit: befad944e231 Merge tag 'drm-fixes-2018-10-05' of git://ano.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=161fc976400000 kernel config: https://syzkaller.appspot.com/x/.config?x=c0af03fe452b65fb dashboard link: https://syzkaller.appspot.com/bug?extid=ec24e95ea483de0a24da compiler: gcc (GCC) 8.0.1 20180413 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10160e3a400000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16995491400000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+ec24e95ea483de0a24da@syzkaller.appspotmail.com ------------[ cut here ]------------ kernel BUG at security/keys/keyring.c:1214! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 5807 Comm: syz-executor226 Not tainted 4.19.0-rc6+ #268 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__key_link_begin+0x23a/0x300 security/keys/keyring.c:1214 Code: fe 48 c7 c7 20 ae 67 89 e8 b3 36 23 fe eb ac e8 ec 64 42 fe 48 c7 c7 20 ae 67 89 e8 30 73 73 04 e9 e3 fe ff ff e8 d6 64 42 fe <0f> 0b e8 cf 64 42 fe 48 8d bb ce 00 00 00 48 b8 00 00 00 00 00 fc RSP: 0018:ffff8801bbdc7b10 EFLAGS: 00010293 RAX: ffff8801d924e2c0 RBX: ffff8801d4e7e080 RCX: ffffffff833c4ebf RDX: 0000000000000000 RSI: ffffffff833c50aa RDI: 0000000000000007 RBP: ffff8801bbdc7b40 R08: ffff8801d924e2c0 R09: fffffbfff12cf4a4 R10: fffffbfff12cf4a4 R11: ffffffff8967a523 R12: ffff8801bbdc7c48 R13: 0000000000000000 R14: ffff8801d4e7e200 R15: ffff8801d4e7e080 FS: 0000000001ce9880(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020cab000 CR3: 00000001d829a000 CR4: 00000000001406f0 Call Trace: construct_alloc_key security/keys/request_key.c:389 [inline] construct_key_and_link security/keys/request_key.c:480 [inline] request_key_and_link+0x737/0x17a0 security/keys/request_key.c:593 __do_sys_request_key security/keys/keyctl.c:213 [inline] __se_sys_request_key security/keys/keyctl.c:158 [inline] __x64_sys_request_key+0x305/0x400 security/keys/keyctl.c:158 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x440169 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffd70324808 EFLAGS: 00000217 ORIG_RAX: 00000000000000f9 RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440169 RDX: 00000000200001c0 RSI: 0000000020000180 RDI: 00000000200000c0 RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 R10: 00000000111522d3 R11: 0000000000000217 R12: 00000000004019f0 R13: 0000000000401a80 R14: 0000000000000000 R15: 0000000000000000 Modules linked in: ---[ end trace 40815c4a8f1e2472 ]--- RIP: 0010:__key_link_begin+0x23a/0x300 security/keys/keyring.c:1214 Code: fe 48 c7 c7 20 ae 67 89 e8 b3 36 23 fe eb ac e8 ec 64 42 fe 48 c7 c7 20 ae 67 89 e8 30 73 73 04 e9 e3 fe ff ff e8 d6 64 42 fe <0f> 0b e8 cf 64 42 fe 48 8d bb ce 00 00 00 48 b8 00 00 00 00 00 fc RSP: 0018:ffff8801bbdc7b10 EFLAGS: 00010293 RAX: ffff8801d924e2c0 RBX: ffff8801d4e7e080 RCX: ffffffff833c4ebf RDX: 0000000000000000 RSI: ffffffff833c50aa RDI: 0000000000000007 RBP: ffff8801bbdc7b40 R08: ffff8801d924e2c0 R09: fffffbfff12cf4a4 R10: fffffbfff12cf4a4 R11: ffffffff8967a523 R12: ffff8801bbdc7c48 R13: 0000000000000000 R14: ffff8801d4e7e200 R15: ffff8801d4e7e080 FS: 0000000001ce9880(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020cab000 CR3: 00000001d829a000 CR4: 00000000001406f0 --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot. syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH] KEYS: always initialize keyring_index_key::desc_len 2018-10-05 11:16 kernel BUG at security/keys/keyring.c:LINE! syzbot @ 2018-11-02 23:15 ` Eric Biggers 2018-11-03 1:57 ` Eric Biggers 2018-11-03 1:58 ` [PATCH v2] " Eric Biggers 1 sibling, 1 reply; 9+ messages in thread From: Eric Biggers @ 2018-11-02 23:15 UTC (permalink / raw) To: keyrings, David Howells Cc: linux-security-module, linux-kernel, syzkaller-bugs From: Eric Biggers <ebiggers@google.com> syzbot hit the 'BUG_ON(index_key->desc_len == 0);' in __key_link_begin() called from construct_alloc_key() during sys_request_key(), because the length of the key description was never calculated. The problem is that we rely on ->desc_len being initialized by search_process_keyrings(), specifically by search_nested_keyrings(). But, if the process isn't subscribed to any keyrings that never happens. Fix it by always initializing keyring_index_key::desc_len as soon as the description is set, like we already do in some places. The following program reproduces the BUG_ON() when it's run as root and no session keyring has been installed. If it doesn't work, try removing pam_keyinit.so from /etc/pam.d/login and rebooting. #include <stdlib.h> #include <unistd.h> #include <keyutils.h> int main(void) { int id = add_key("keyring", "syz", NULL, 0, KEY_SPEC_USER_KEYRING); keyctl_setperm(id, KEY_OTH_WRITE); setreuid(5000, 5000); request_key("user", "desc", "", id); } Reported-by: syzbot+ec24e95ea483de0a24da@syzkaller.appspotmail.com Fixes: b2a4df200d57 ("KEYS: Expand the capacity of a keyring") Cc: <stable@vger.kernel.org> # v3.13+ Signed-off-by: Eric Biggers <ebiggers@google.com> --- security/keys/keyring.c | 4 +--- security/keys/proc.c | 1 + security/keys/request_key.c | 1 + security/keys/request_key_auth.c | 2 +- 4 files changed, 4 insertions(+), 4 deletions(-) diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 41bcf57e96f2..99a55145ddcd 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -661,9 +661,6 @@ static bool search_nested_keyrings(struct key *keyring, BUG_ON((ctx->flags & STATE_CHECKS) == 0 || (ctx->flags & STATE_CHECKS) == STATE_CHECKS); - if (ctx->index_key.description) - ctx->index_key.desc_len = strlen(ctx->index_key.description); - /* Check to see if this top-level keyring is what we are looking for * and whether it is valid or not. */ @@ -914,6 +911,7 @@ key_ref_t keyring_search(key_ref_t keyring, struct keyring_search_context ctx = { .index_key.type = type, .index_key.description = description, + .index_key.desc_len = strlen(description), .cred = current_cred(), .match_data.cmp = key_default_cmp, .match_data.raw_data = description, diff --git a/security/keys/proc.c b/security/keys/proc.c index 5af2934965d8..909f6c5270a1 100644 --- a/security/keys/proc.c +++ b/security/keys/proc.c @@ -168,6 +168,7 @@ static int proc_keys_show(struct seq_file *m, void *v) struct keyring_search_context ctx = { .index_key.type = key->type, .index_key.description = key->description, + .index_key.desc_len = strlen(key->description), .cred = m->file->f_cred, .match_data.cmp = lookup_user_key_possessed, .match_data.raw_data = key, diff --git a/security/keys/request_key.c b/security/keys/request_key.c index 114f7408feee..738553698649 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -545,6 +545,7 @@ struct key *request_key_and_link(struct key_type *type, struct keyring_search_context ctx = { .index_key.type = type, .index_key.description = description, + .index_key.desc_len = strlen(description), .cred = current_cred(), .match_data.cmp = key_default_cmp, .match_data.raw_data = description, diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c index 424e1d90412e..6797843154f0 100644 --- a/security/keys/request_key_auth.c +++ b/security/keys/request_key_auth.c @@ -246,7 +246,7 @@ struct key *key_get_instantiation_authkey(key_serial_t target_id) struct key *authkey; key_ref_t authkey_ref; - sprintf(description, "%x", target_id); + ctx.index_key.desc_len = sprintf(description, "%x", target_id); authkey_ref = search_process_keyrings(&ctx); -- 2.19.1.930.g4563a0d9d0-goog ^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH] KEYS: always initialize keyring_index_key::desc_len 2018-11-02 23:15 ` [PATCH] KEYS: always initialize keyring_index_key::desc_len Eric Biggers @ 2018-11-03 1:57 ` Eric Biggers 0 siblings, 0 replies; 9+ messages in thread From: Eric Biggers @ 2018-11-03 1:57 UTC (permalink / raw) To: keyrings, David Howells Cc: linux-security-module, linux-kernel, syzkaller-bugs On Fri, Nov 02, 2018 at 04:15:10PM -0700, Eric Biggers wrote: > From: Eric Biggers <ebiggers@google.com> > > syzbot hit the 'BUG_ON(index_key->desc_len == 0);' in __key_link_begin() > called from construct_alloc_key() during sys_request_key(), because the > length of the key description was never calculated. > > The problem is that we rely on ->desc_len being initialized by > search_process_keyrings(), specifically by search_nested_keyrings(). > But, if the process isn't subscribed to any keyrings that never happens. > > Fix it by always initializing keyring_index_key::desc_len as soon as the > description is set, like we already do in some places. > > The following program reproduces the BUG_ON() when it's run as root and > no session keyring has been installed. If it doesn't work, try removing > pam_keyinit.so from /etc/pam.d/login and rebooting. > > #include <stdlib.h> > #include <unistd.h> > #include <keyutils.h> > > int main(void) > { > int id = add_key("keyring", "syz", NULL, 0, KEY_SPEC_USER_KEYRING); > > keyctl_setperm(id, KEY_OTH_WRITE); > setreuid(5000, 5000); > request_key("user", "desc", "", id); > } > > Reported-by: syzbot+ec24e95ea483de0a24da@syzkaller.appspotmail.com > Fixes: b2a4df200d57 ("KEYS: Expand the capacity of a keyring") > Cc: <stable@vger.kernel.org> # v3.13+ > Signed-off-by: Eric Biggers <ebiggers@google.com> > --- > security/keys/keyring.c | 4 +--- > security/keys/proc.c | 1 + > security/keys/request_key.c | 1 + > security/keys/request_key_auth.c | 2 +- > 4 files changed, 4 insertions(+), 4 deletions(-) > > diff --git a/security/keys/keyring.c b/security/keys/keyring.c > index 41bcf57e96f2..99a55145ddcd 100644 > --- a/security/keys/keyring.c > +++ b/security/keys/keyring.c > @@ -661,9 +661,6 @@ static bool search_nested_keyrings(struct key *keyring, > BUG_ON((ctx->flags & STATE_CHECKS) == 0 || > (ctx->flags & STATE_CHECKS) == STATE_CHECKS); > > - if (ctx->index_key.description) > - ctx->index_key.desc_len = strlen(ctx->index_key.description); > - > /* Check to see if this top-level keyring is what we are looking for > * and whether it is valid or not. > */ > @@ -914,6 +911,7 @@ key_ref_t keyring_search(key_ref_t keyring, > struct keyring_search_context ctx = { > .index_key.type = type, > .index_key.description = description, > + .index_key.desc_len = strlen(description), > .cred = current_cred(), > .match_data.cmp = key_default_cmp, > .match_data.raw_data = description, > diff --git a/security/keys/proc.c b/security/keys/proc.c > index 5af2934965d8..909f6c5270a1 100644 > --- a/security/keys/proc.c > +++ b/security/keys/proc.c > @@ -168,6 +168,7 @@ static int proc_keys_show(struct seq_file *m, void *v) > struct keyring_search_context ctx = { > .index_key.type = key->type, > .index_key.description = key->description, > + .index_key.desc_len = strlen(key->description), > .cred = m->file->f_cred, > .match_data.cmp = lookup_user_key_possessed, > .match_data.raw_data = key, It's actually possible to just set '.index_key = key->index_key' here. I'll send v2 with that instead. - Eric ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v2] KEYS: always initialize keyring_index_key::desc_len 2018-10-05 11:16 kernel BUG at security/keys/keyring.c:LINE! syzbot 2018-11-02 23:15 ` [PATCH] KEYS: always initialize keyring_index_key::desc_len Eric Biggers @ 2018-11-03 1:58 ` Eric Biggers 2018-11-28 23:19 ` Eric Biggers 1 sibling, 1 reply; 9+ messages in thread From: Eric Biggers @ 2018-11-03 1:58 UTC (permalink / raw) To: keyrings, David Howells Cc: linux-security-module, linux-kernel, syzkaller-bugs From: Eric Biggers <ebiggers@google.com> syzbot hit the 'BUG_ON(index_key->desc_len == 0);' in __key_link_begin() called from construct_alloc_key() during sys_request_key(), because the length of the key description was never calculated. The problem is that we rely on ->desc_len being initialized by search_process_keyrings(), specifically by search_nested_keyrings(). But, if the process isn't subscribed to any keyrings that never happens. Fix it by always initializing keyring_index_key::desc_len as soon as the description is set, like we already do in some places. The following program reproduces the BUG_ON() when it's run as root and no session keyring has been installed. If it doesn't work, try removing pam_keyinit.so from /etc/pam.d/login and rebooting. #include <stdlib.h> #include <unistd.h> #include <keyutils.h> int main(void) { int id = add_key("keyring", "syz", NULL, 0, KEY_SPEC_USER_KEYRING); keyctl_setperm(id, KEY_OTH_WRITE); setreuid(5000, 5000); request_key("user", "desc", "", id); } Reported-by: syzbot+ec24e95ea483de0a24da@syzkaller.appspotmail.com Fixes: b2a4df200d57 ("KEYS: Expand the capacity of a keyring") Cc: <stable@vger.kernel.org> # v3.13+ Signed-off-by: Eric Biggers <ebiggers@google.com> --- v2: In proc_keys_show(), assign index_key directly security/keys/keyring.c | 4 +--- security/keys/proc.c | 3 +-- security/keys/request_key.c | 1 + security/keys/request_key_auth.c | 2 +- 4 files changed, 4 insertions(+), 6 deletions(-) diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 41bcf57e96f21..99a55145ddcd2 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -661,9 +661,6 @@ static bool search_nested_keyrings(struct key *keyring, BUG_ON((ctx->flags & STATE_CHECKS) == 0 || (ctx->flags & STATE_CHECKS) == STATE_CHECKS); - if (ctx->index_key.description) - ctx->index_key.desc_len = strlen(ctx->index_key.description); - /* Check to see if this top-level keyring is what we are looking for * and whether it is valid or not. */ @@ -914,6 +911,7 @@ key_ref_t keyring_search(key_ref_t keyring, struct keyring_search_context ctx = { .index_key.type = type, .index_key.description = description, + .index_key.desc_len = strlen(description), .cred = current_cred(), .match_data.cmp = key_default_cmp, .match_data.raw_data = description, diff --git a/security/keys/proc.c b/security/keys/proc.c index 5af2934965d80..d38be9db2cc07 100644 --- a/security/keys/proc.c +++ b/security/keys/proc.c @@ -166,8 +166,7 @@ static int proc_keys_show(struct seq_file *m, void *v) int rc; struct keyring_search_context ctx = { - .index_key.type = key->type, - .index_key.description = key->description, + .index_key = key->index_key, .cred = m->file->f_cred, .match_data.cmp = lookup_user_key_possessed, .match_data.raw_data = key, diff --git a/security/keys/request_key.c b/security/keys/request_key.c index 114f7408feee6..7385536986497 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -545,6 +545,7 @@ struct key *request_key_and_link(struct key_type *type, struct keyring_search_context ctx = { .index_key.type = type, .index_key.description = description, + .index_key.desc_len = strlen(description), .cred = current_cred(), .match_data.cmp = key_default_cmp, .match_data.raw_data = description, diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c index 424e1d90412ea..6797843154f03 100644 --- a/security/keys/request_key_auth.c +++ b/security/keys/request_key_auth.c @@ -246,7 +246,7 @@ struct key *key_get_instantiation_authkey(key_serial_t target_id) struct key *authkey; key_ref_t authkey_ref; - sprintf(description, "%x", target_id); + ctx.index_key.desc_len = sprintf(description, "%x", target_id); authkey_ref = search_process_keyrings(&ctx); -- 2.19.1 ^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH v2] KEYS: always initialize keyring_index_key::desc_len 2018-11-03 1:58 ` [PATCH v2] " Eric Biggers @ 2018-11-28 23:19 ` Eric Biggers 2018-12-06 18:26 ` Eric Biggers 2019-01-10 20:27 ` Eric Biggers 0 siblings, 2 replies; 9+ messages in thread From: Eric Biggers @ 2018-11-28 23:19 UTC (permalink / raw) To: keyrings, David Howells Cc: linux-security-module, linux-kernel, syzkaller-bugs On Fri, Nov 02, 2018 at 06:58:54PM -0700, Eric Biggers wrote: > From: Eric Biggers <ebiggers@google.com> > > syzbot hit the 'BUG_ON(index_key->desc_len == 0);' in __key_link_begin() > called from construct_alloc_key() during sys_request_key(), because the > length of the key description was never calculated. > > The problem is that we rely on ->desc_len being initialized by > search_process_keyrings(), specifically by search_nested_keyrings(). > But, if the process isn't subscribed to any keyrings that never happens. > > Fix it by always initializing keyring_index_key::desc_len as soon as the > description is set, like we already do in some places. > > The following program reproduces the BUG_ON() when it's run as root and > no session keyring has been installed. If it doesn't work, try removing > pam_keyinit.so from /etc/pam.d/login and rebooting. > > #include <stdlib.h> > #include <unistd.h> > #include <keyutils.h> > > int main(void) > { > int id = add_key("keyring", "syz", NULL, 0, KEY_SPEC_USER_KEYRING); > > keyctl_setperm(id, KEY_OTH_WRITE); > setreuid(5000, 5000); > request_key("user", "desc", "", id); > } > > Reported-by: syzbot+ec24e95ea483de0a24da@syzkaller.appspotmail.com > Fixes: b2a4df200d57 ("KEYS: Expand the capacity of a keyring") > Cc: <stable@vger.kernel.org> # v3.13+ > Signed-off-by: Eric Biggers <ebiggers@google.com> > --- > > v2: In proc_keys_show(), assign index_key directly > > security/keys/keyring.c | 4 +--- > security/keys/proc.c | 3 +-- > security/keys/request_key.c | 1 + > security/keys/request_key_auth.c | 2 +- > 4 files changed, 4 insertions(+), 6 deletions(-) > > diff --git a/security/keys/keyring.c b/security/keys/keyring.c > index 41bcf57e96f21..99a55145ddcd2 100644 > --- a/security/keys/keyring.c > +++ b/security/keys/keyring.c > @@ -661,9 +661,6 @@ static bool search_nested_keyrings(struct key *keyring, > BUG_ON((ctx->flags & STATE_CHECKS) == 0 || > (ctx->flags & STATE_CHECKS) == STATE_CHECKS); > > - if (ctx->index_key.description) > - ctx->index_key.desc_len = strlen(ctx->index_key.description); > - > /* Check to see if this top-level keyring is what we are looking for > * and whether it is valid or not. > */ > @@ -914,6 +911,7 @@ key_ref_t keyring_search(key_ref_t keyring, > struct keyring_search_context ctx = { > .index_key.type = type, > .index_key.description = description, > + .index_key.desc_len = strlen(description), > .cred = current_cred(), > .match_data.cmp = key_default_cmp, > .match_data.raw_data = description, > diff --git a/security/keys/proc.c b/security/keys/proc.c > index 5af2934965d80..d38be9db2cc07 100644 > --- a/security/keys/proc.c > +++ b/security/keys/proc.c > @@ -166,8 +166,7 @@ static int proc_keys_show(struct seq_file *m, void *v) > int rc; > > struct keyring_search_context ctx = { > - .index_key.type = key->type, > - .index_key.description = key->description, > + .index_key = key->index_key, > .cred = m->file->f_cred, > .match_data.cmp = lookup_user_key_possessed, > .match_data.raw_data = key, > diff --git a/security/keys/request_key.c b/security/keys/request_key.c > index 114f7408feee6..7385536986497 100644 > --- a/security/keys/request_key.c > +++ b/security/keys/request_key.c > @@ -545,6 +545,7 @@ struct key *request_key_and_link(struct key_type *type, > struct keyring_search_context ctx = { > .index_key.type = type, > .index_key.description = description, > + .index_key.desc_len = strlen(description), > .cred = current_cred(), > .match_data.cmp = key_default_cmp, > .match_data.raw_data = description, > diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c > index 424e1d90412ea..6797843154f03 100644 > --- a/security/keys/request_key_auth.c > +++ b/security/keys/request_key_auth.c > @@ -246,7 +246,7 @@ struct key *key_get_instantiation_authkey(key_serial_t target_id) > struct key *authkey; > key_ref_t authkey_ref; > > - sprintf(description, "%x", target_id); > + ctx.index_key.desc_len = sprintf(description, "%x", target_id); > > authkey_ref = search_process_keyrings(&ctx); > > -- > 2.19.1 > Ping. David, are you planning to apply this? - Eric ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2] KEYS: always initialize keyring_index_key::desc_len 2018-11-28 23:19 ` Eric Biggers @ 2018-12-06 18:26 ` Eric Biggers 2019-01-10 20:27 ` Eric Biggers 1 sibling, 0 replies; 9+ messages in thread From: Eric Biggers @ 2018-12-06 18:26 UTC (permalink / raw) To: keyrings, David Howells Cc: linux-security-module, linux-kernel, syzkaller-bugs On Wed, Nov 28, 2018 at 03:19:41PM -0800, Eric Biggers wrote: > On Fri, Nov 02, 2018 at 06:58:54PM -0700, Eric Biggers wrote: > > From: Eric Biggers <ebiggers@google.com> > > > > syzbot hit the 'BUG_ON(index_key->desc_len == 0);' in __key_link_begin() > > called from construct_alloc_key() during sys_request_key(), because the > > length of the key description was never calculated. > > > > The problem is that we rely on ->desc_len being initialized by > > search_process_keyrings(), specifically by search_nested_keyrings(). > > But, if the process isn't subscribed to any keyrings that never happens. > > > > Fix it by always initializing keyring_index_key::desc_len as soon as the > > description is set, like we already do in some places. > > > > The following program reproduces the BUG_ON() when it's run as root and > > no session keyring has been installed. If it doesn't work, try removing > > pam_keyinit.so from /etc/pam.d/login and rebooting. > > > > #include <stdlib.h> > > #include <unistd.h> > > #include <keyutils.h> > > > > int main(void) > > { > > int id = add_key("keyring", "syz", NULL, 0, KEY_SPEC_USER_KEYRING); > > > > keyctl_setperm(id, KEY_OTH_WRITE); > > setreuid(5000, 5000); > > request_key("user", "desc", "", id); > > } > > > > Reported-by: syzbot+ec24e95ea483de0a24da@syzkaller.appspotmail.com > > Fixes: b2a4df200d57 ("KEYS: Expand the capacity of a keyring") > > Cc: <stable@vger.kernel.org> # v3.13+ > > Signed-off-by: Eric Biggers <ebiggers@google.com> > > --- > > > > v2: In proc_keys_show(), assign index_key directly > > > > security/keys/keyring.c | 4 +--- > > security/keys/proc.c | 3 +-- > > security/keys/request_key.c | 1 + > > security/keys/request_key_auth.c | 2 +- > > 4 files changed, 4 insertions(+), 6 deletions(-) > > > > diff --git a/security/keys/keyring.c b/security/keys/keyring.c > > index 41bcf57e96f21..99a55145ddcd2 100644 > > --- a/security/keys/keyring.c > > +++ b/security/keys/keyring.c > > @@ -661,9 +661,6 @@ static bool search_nested_keyrings(struct key *keyring, > > BUG_ON((ctx->flags & STATE_CHECKS) == 0 || > > (ctx->flags & STATE_CHECKS) == STATE_CHECKS); > > > > - if (ctx->index_key.description) > > - ctx->index_key.desc_len = strlen(ctx->index_key.description); > > - > > /* Check to see if this top-level keyring is what we are looking for > > * and whether it is valid or not. > > */ > > @@ -914,6 +911,7 @@ key_ref_t keyring_search(key_ref_t keyring, > > struct keyring_search_context ctx = { > > .index_key.type = type, > > .index_key.description = description, > > + .index_key.desc_len = strlen(description), > > .cred = current_cred(), > > .match_data.cmp = key_default_cmp, > > .match_data.raw_data = description, > > diff --git a/security/keys/proc.c b/security/keys/proc.c > > index 5af2934965d80..d38be9db2cc07 100644 > > --- a/security/keys/proc.c > > +++ b/security/keys/proc.c > > @@ -166,8 +166,7 @@ static int proc_keys_show(struct seq_file *m, void *v) > > int rc; > > > > struct keyring_search_context ctx = { > > - .index_key.type = key->type, > > - .index_key.description = key->description, > > + .index_key = key->index_key, > > .cred = m->file->f_cred, > > .match_data.cmp = lookup_user_key_possessed, > > .match_data.raw_data = key, > > diff --git a/security/keys/request_key.c b/security/keys/request_key.c > > index 114f7408feee6..7385536986497 100644 > > --- a/security/keys/request_key.c > > +++ b/security/keys/request_key.c > > @@ -545,6 +545,7 @@ struct key *request_key_and_link(struct key_type *type, > > struct keyring_search_context ctx = { > > .index_key.type = type, > > .index_key.description = description, > > + .index_key.desc_len = strlen(description), > > .cred = current_cred(), > > .match_data.cmp = key_default_cmp, > > .match_data.raw_data = description, > > diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c > > index 424e1d90412ea..6797843154f03 100644 > > --- a/security/keys/request_key_auth.c > > +++ b/security/keys/request_key_auth.c > > @@ -246,7 +246,7 @@ struct key *key_get_instantiation_authkey(key_serial_t target_id) > > struct key *authkey; > > key_ref_t authkey_ref; > > > > - sprintf(description, "%x", target_id); > > + ctx.index_key.desc_len = sprintf(description, "%x", target_id); > > > > authkey_ref = search_process_keyrings(&ctx); > > > > -- > > 2.19.1 > > > > Ping. David, are you planning to apply this? > > - Eric > Ping. ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2] KEYS: always initialize keyring_index_key::desc_len 2018-11-28 23:19 ` Eric Biggers 2018-12-06 18:26 ` Eric Biggers @ 2019-01-10 20:27 ` Eric Biggers 2019-02-07 23:35 ` Eric Biggers 1 sibling, 1 reply; 9+ messages in thread From: Eric Biggers @ 2019-01-10 20:27 UTC (permalink / raw) To: keyrings, David Howells Cc: linux-security-module, linux-kernel, syzkaller-bugs On Wed, Nov 28, 2018 at 03:19:41PM -0800, Eric Biggers wrote: > On Fri, Nov 02, 2018 at 06:58:54PM -0700, Eric Biggers wrote: > > From: Eric Biggers <ebiggers@google.com> > > > > syzbot hit the 'BUG_ON(index_key->desc_len == 0);' in __key_link_begin() > > called from construct_alloc_key() during sys_request_key(), because the > > length of the key description was never calculated. > > > > The problem is that we rely on ->desc_len being initialized by > > search_process_keyrings(), specifically by search_nested_keyrings(). > > But, if the process isn't subscribed to any keyrings that never happens. > > > > Fix it by always initializing keyring_index_key::desc_len as soon as the > > description is set, like we already do in some places. > > > > The following program reproduces the BUG_ON() when it's run as root and > > no session keyring has been installed. If it doesn't work, try removing > > pam_keyinit.so from /etc/pam.d/login and rebooting. > > > > #include <stdlib.h> > > #include <unistd.h> > > #include <keyutils.h> > > > > int main(void) > > { > > int id = add_key("keyring", "syz", NULL, 0, KEY_SPEC_USER_KEYRING); > > > > keyctl_setperm(id, KEY_OTH_WRITE); > > setreuid(5000, 5000); > > request_key("user", "desc", "", id); > > } > > > > Reported-by: syzbot+ec24e95ea483de0a24da@syzkaller.appspotmail.com > > Fixes: b2a4df200d57 ("KEYS: Expand the capacity of a keyring") > > Cc: <stable@vger.kernel.org> # v3.13+ > > Signed-off-by: Eric Biggers <ebiggers@google.com> > > --- > > > > v2: In proc_keys_show(), assign index_key directly > > > > security/keys/keyring.c | 4 +--- > > security/keys/proc.c | 3 +-- > > security/keys/request_key.c | 1 + > > security/keys/request_key_auth.c | 2 +- > > 4 files changed, 4 insertions(+), 6 deletions(-) > > > > diff --git a/security/keys/keyring.c b/security/keys/keyring.c > > index 41bcf57e96f21..99a55145ddcd2 100644 > > --- a/security/keys/keyring.c > > +++ b/security/keys/keyring.c > > @@ -661,9 +661,6 @@ static bool search_nested_keyrings(struct key *keyring, > > BUG_ON((ctx->flags & STATE_CHECKS) == 0 || > > (ctx->flags & STATE_CHECKS) == STATE_CHECKS); > > > > - if (ctx->index_key.description) > > - ctx->index_key.desc_len = strlen(ctx->index_key.description); > > - > > /* Check to see if this top-level keyring is what we are looking for > > * and whether it is valid or not. > > */ > > @@ -914,6 +911,7 @@ key_ref_t keyring_search(key_ref_t keyring, > > struct keyring_search_context ctx = { > > .index_key.type = type, > > .index_key.description = description, > > + .index_key.desc_len = strlen(description), > > .cred = current_cred(), > > .match_data.cmp = key_default_cmp, > > .match_data.raw_data = description, > > diff --git a/security/keys/proc.c b/security/keys/proc.c > > index 5af2934965d80..d38be9db2cc07 100644 > > --- a/security/keys/proc.c > > +++ b/security/keys/proc.c > > @@ -166,8 +166,7 @@ static int proc_keys_show(struct seq_file *m, void *v) > > int rc; > > > > struct keyring_search_context ctx = { > > - .index_key.type = key->type, > > - .index_key.description = key->description, > > + .index_key = key->index_key, > > .cred = m->file->f_cred, > > .match_data.cmp = lookup_user_key_possessed, > > .match_data.raw_data = key, > > diff --git a/security/keys/request_key.c b/security/keys/request_key.c > > index 114f7408feee6..7385536986497 100644 > > --- a/security/keys/request_key.c > > +++ b/security/keys/request_key.c > > @@ -545,6 +545,7 @@ struct key *request_key_and_link(struct key_type *type, > > struct keyring_search_context ctx = { > > .index_key.type = type, > > .index_key.description = description, > > + .index_key.desc_len = strlen(description), > > .cred = current_cred(), > > .match_data.cmp = key_default_cmp, > > .match_data.raw_data = description, > > diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c > > index 424e1d90412ea..6797843154f03 100644 > > --- a/security/keys/request_key_auth.c > > +++ b/security/keys/request_key_auth.c > > @@ -246,7 +246,7 @@ struct key *key_get_instantiation_authkey(key_serial_t target_id) > > struct key *authkey; > > key_ref_t authkey_ref; > > > > - sprintf(description, "%x", target_id); > > + ctx.index_key.desc_len = sprintf(description, "%x", target_id); > > > > authkey_ref = search_process_keyrings(&ctx); > > > > -- > > 2.19.1 > > > > Ping. David, are you planning to apply this? > > - Eric > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/20181128231940.GB131170%40gmail.com. > For more options, visit https://groups.google.com/d/optout. Ping. ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2] KEYS: always initialize keyring_index_key::desc_len 2019-01-10 20:27 ` Eric Biggers @ 2019-02-07 23:35 ` Eric Biggers 2019-02-19 23:04 ` Eric Biggers 0 siblings, 1 reply; 9+ messages in thread From: Eric Biggers @ 2019-02-07 23:35 UTC (permalink / raw) To: keyrings, David Howells Cc: linux-security-module, linux-kernel, syzkaller-bugs On Thu, Jan 10, 2019 at 12:27:46PM -0800, Eric Biggers wrote: > On Wed, Nov 28, 2018 at 03:19:41PM -0800, Eric Biggers wrote: > > On Fri, Nov 02, 2018 at 06:58:54PM -0700, Eric Biggers wrote: > > > From: Eric Biggers <ebiggers@google.com> > > > > > > syzbot hit the 'BUG_ON(index_key->desc_len == 0);' in __key_link_begin() > > > called from construct_alloc_key() during sys_request_key(), because the > > > length of the key description was never calculated. > > > > > > The problem is that we rely on ->desc_len being initialized by > > > search_process_keyrings(), specifically by search_nested_keyrings(). > > > But, if the process isn't subscribed to any keyrings that never happens. > > > > > > Fix it by always initializing keyring_index_key::desc_len as soon as the > > > description is set, like we already do in some places. > > > > > > The following program reproduces the BUG_ON() when it's run as root and > > > no session keyring has been installed. If it doesn't work, try removing > > > pam_keyinit.so from /etc/pam.d/login and rebooting. > > > > > > #include <stdlib.h> > > > #include <unistd.h> > > > #include <keyutils.h> > > > > > > int main(void) > > > { > > > int id = add_key("keyring", "syz", NULL, 0, KEY_SPEC_USER_KEYRING); > > > > > > keyctl_setperm(id, KEY_OTH_WRITE); > > > setreuid(5000, 5000); > > > request_key("user", "desc", "", id); > > > } > > > > > > Reported-by: syzbot+ec24e95ea483de0a24da@syzkaller.appspotmail.com > > > Fixes: b2a4df200d57 ("KEYS: Expand the capacity of a keyring") > > > Cc: <stable@vger.kernel.org> # v3.13+ > > > Signed-off-by: Eric Biggers <ebiggers@google.com> > > > --- > > > > > > v2: In proc_keys_show(), assign index_key directly > > > > > > security/keys/keyring.c | 4 +--- > > > security/keys/proc.c | 3 +-- > > > security/keys/request_key.c | 1 + > > > security/keys/request_key_auth.c | 2 +- > > > 4 files changed, 4 insertions(+), 6 deletions(-) > > > > > > diff --git a/security/keys/keyring.c b/security/keys/keyring.c > > > index 41bcf57e96f21..99a55145ddcd2 100644 > > > --- a/security/keys/keyring.c > > > +++ b/security/keys/keyring.c > > > @@ -661,9 +661,6 @@ static bool search_nested_keyrings(struct key *keyring, > > > BUG_ON((ctx->flags & STATE_CHECKS) == 0 || > > > (ctx->flags & STATE_CHECKS) == STATE_CHECKS); > > > > > > - if (ctx->index_key.description) > > > - ctx->index_key.desc_len = strlen(ctx->index_key.description); > > > - > > > /* Check to see if this top-level keyring is what we are looking for > > > * and whether it is valid or not. > > > */ > > > @@ -914,6 +911,7 @@ key_ref_t keyring_search(key_ref_t keyring, > > > struct keyring_search_context ctx = { > > > .index_key.type = type, > > > .index_key.description = description, > > > + .index_key.desc_len = strlen(description), > > > .cred = current_cred(), > > > .match_data.cmp = key_default_cmp, > > > .match_data.raw_data = description, > > > diff --git a/security/keys/proc.c b/security/keys/proc.c > > > index 5af2934965d80..d38be9db2cc07 100644 > > > --- a/security/keys/proc.c > > > +++ b/security/keys/proc.c > > > @@ -166,8 +166,7 @@ static int proc_keys_show(struct seq_file *m, void *v) > > > int rc; > > > > > > struct keyring_search_context ctx = { > > > - .index_key.type = key->type, > > > - .index_key.description = key->description, > > > + .index_key = key->index_key, > > > .cred = m->file->f_cred, > > > .match_data.cmp = lookup_user_key_possessed, > > > .match_data.raw_data = key, > > > diff --git a/security/keys/request_key.c b/security/keys/request_key.c > > > index 114f7408feee6..7385536986497 100644 > > > --- a/security/keys/request_key.c > > > +++ b/security/keys/request_key.c > > > @@ -545,6 +545,7 @@ struct key *request_key_and_link(struct key_type *type, > > > struct keyring_search_context ctx = { > > > .index_key.type = type, > > > .index_key.description = description, > > > + .index_key.desc_len = strlen(description), > > > .cred = current_cred(), > > > .match_data.cmp = key_default_cmp, > > > .match_data.raw_data = description, > > > diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c > > > index 424e1d90412ea..6797843154f03 100644 > > > --- a/security/keys/request_key_auth.c > > > +++ b/security/keys/request_key_auth.c > > > @@ -246,7 +246,7 @@ struct key *key_get_instantiation_authkey(key_serial_t target_id) > > > struct key *authkey; > > > key_ref_t authkey_ref; > > > > > > - sprintf(description, "%x", target_id); > > > + ctx.index_key.desc_len = sprintf(description, "%x", target_id); > > > > > > authkey_ref = search_process_keyrings(&ctx); > > > > > > -- > > > 2.19.1 > > > > > > > Ping. David, are you planning to apply this? > > > > - Eric > > > > -- > > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/20181128231940.GB131170%40gmail.com. > > For more options, visit https://groups.google.com/d/optout. > > Ping. > Ping. David, are you planning to apply this? - Eric ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2] KEYS: always initialize keyring_index_key::desc_len 2019-02-07 23:35 ` Eric Biggers @ 2019-02-19 23:04 ` Eric Biggers 0 siblings, 0 replies; 9+ messages in thread From: Eric Biggers @ 2019-02-19 23:04 UTC (permalink / raw) To: James Morris Cc: keyrings, David Howells, linux-security-module, linux-kernel, syzkaller-bugs On Thu, Feb 07, 2019 at 03:35:29PM -0800, Eric Biggers wrote: > On Thu, Jan 10, 2019 at 12:27:46PM -0800, Eric Biggers wrote: > > On Wed, Nov 28, 2018 at 03:19:41PM -0800, Eric Biggers wrote: > > > On Fri, Nov 02, 2018 at 06:58:54PM -0700, Eric Biggers wrote: > > > > From: Eric Biggers <ebiggers@google.com> > > > > > > > > syzbot hit the 'BUG_ON(index_key->desc_len == 0);' in __key_link_begin() > > > > called from construct_alloc_key() during sys_request_key(), because the > > > > length of the key description was never calculated. > > > > > > > > The problem is that we rely on ->desc_len being initialized by > > > > search_process_keyrings(), specifically by search_nested_keyrings(). > > > > But, if the process isn't subscribed to any keyrings that never happens. > > > > > > > > Fix it by always initializing keyring_index_key::desc_len as soon as the > > > > description is set, like we already do in some places. > > > > > > > > The following program reproduces the BUG_ON() when it's run as root and > > > > no session keyring has been installed. If it doesn't work, try removing > > > > pam_keyinit.so from /etc/pam.d/login and rebooting. > > > > > > > > #include <stdlib.h> > > > > #include <unistd.h> > > > > #include <keyutils.h> > > > > > > > > int main(void) > > > > { > > > > int id = add_key("keyring", "syz", NULL, 0, KEY_SPEC_USER_KEYRING); > > > > > > > > keyctl_setperm(id, KEY_OTH_WRITE); > > > > setreuid(5000, 5000); > > > > request_key("user", "desc", "", id); > > > > } > > > > > > > > Reported-by: syzbot+ec24e95ea483de0a24da@syzkaller.appspotmail.com > > > > Fixes: b2a4df200d57 ("KEYS: Expand the capacity of a keyring") > > > > Cc: <stable@vger.kernel.org> # v3.13+ > > > > Signed-off-by: Eric Biggers <ebiggers@google.com> > > > > --- > > > > > > > > v2: In proc_keys_show(), assign index_key directly > > > > > > > > security/keys/keyring.c | 4 +--- > > > > security/keys/proc.c | 3 +-- > > > > security/keys/request_key.c | 1 + > > > > security/keys/request_key_auth.c | 2 +- > > > > 4 files changed, 4 insertions(+), 6 deletions(-) > > > > > > > > diff --git a/security/keys/keyring.c b/security/keys/keyring.c > > > > index 41bcf57e96f21..99a55145ddcd2 100644 > > > > --- a/security/keys/keyring.c > > > > +++ b/security/keys/keyring.c > > > > @@ -661,9 +661,6 @@ static bool search_nested_keyrings(struct key *keyring, > > > > BUG_ON((ctx->flags & STATE_CHECKS) == 0 || > > > > (ctx->flags & STATE_CHECKS) == STATE_CHECKS); > > > > > > > > - if (ctx->index_key.description) > > > > - ctx->index_key.desc_len = strlen(ctx->index_key.description); > > > > - > > > > /* Check to see if this top-level keyring is what we are looking for > > > > * and whether it is valid or not. > > > > */ > > > > @@ -914,6 +911,7 @@ key_ref_t keyring_search(key_ref_t keyring, > > > > struct keyring_search_context ctx = { > > > > .index_key.type = type, > > > > .index_key.description = description, > > > > + .index_key.desc_len = strlen(description), > > > > .cred = current_cred(), > > > > .match_data.cmp = key_default_cmp, > > > > .match_data.raw_data = description, > > > > diff --git a/security/keys/proc.c b/security/keys/proc.c > > > > index 5af2934965d80..d38be9db2cc07 100644 > > > > --- a/security/keys/proc.c > > > > +++ b/security/keys/proc.c > > > > @@ -166,8 +166,7 @@ static int proc_keys_show(struct seq_file *m, void *v) > > > > int rc; > > > > > > > > struct keyring_search_context ctx = { > > > > - .index_key.type = key->type, > > > > - .index_key.description = key->description, > > > > + .index_key = key->index_key, > > > > .cred = m->file->f_cred, > > > > .match_data.cmp = lookup_user_key_possessed, > > > > .match_data.raw_data = key, > > > > diff --git a/security/keys/request_key.c b/security/keys/request_key.c > > > > index 114f7408feee6..7385536986497 100644 > > > > --- a/security/keys/request_key.c > > > > +++ b/security/keys/request_key.c > > > > @@ -545,6 +545,7 @@ struct key *request_key_and_link(struct key_type *type, > > > > struct keyring_search_context ctx = { > > > > .index_key.type = type, > > > > .index_key.description = description, > > > > + .index_key.desc_len = strlen(description), > > > > .cred = current_cred(), > > > > .match_data.cmp = key_default_cmp, > > > > .match_data.raw_data = description, > > > > diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c > > > > index 424e1d90412ea..6797843154f03 100644 > > > > --- a/security/keys/request_key_auth.c > > > > +++ b/security/keys/request_key_auth.c > > > > @@ -246,7 +246,7 @@ struct key *key_get_instantiation_authkey(key_serial_t target_id) > > > > struct key *authkey; > > > > key_ref_t authkey_ref; > > > > > > > > - sprintf(description, "%x", target_id); > > > > + ctx.index_key.desc_len = sprintf(description, "%x", target_id); > > > > > > > > authkey_ref = search_process_keyrings(&ctx); > > > > > > > > -- > > > > 2.19.1 > > > > > > > > > > Ping. David, are you planning to apply this? > > > > > > - Eric > > > > > > -- > > > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > > > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > > > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/20181128231940.GB131170%40gmail.com. > > > For more options, visit https://groups.google.com/d/optout. > > > > Ping. > > > > Ping. David, are you planning to apply this? > > - Eric Hi James, can you please apply this for v5.1? This has been ignored by David for over 3 months with repeated pings. - Eric ^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2019-02-19 23:04 UTC | newest] Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2018-10-05 11:16 kernel BUG at security/keys/keyring.c:LINE! syzbot 2018-11-02 23:15 ` [PATCH] KEYS: always initialize keyring_index_key::desc_len Eric Biggers 2018-11-03 1:57 ` Eric Biggers 2018-11-03 1:58 ` [PATCH v2] " Eric Biggers 2018-11-28 23:19 ` Eric Biggers 2018-12-06 18:26 ` Eric Biggers 2019-01-10 20:27 ` Eric Biggers 2019-02-07 23:35 ` Eric Biggers 2019-02-19 23:04 ` Eric Biggers
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