* [PATCH] cifs: fix leak in cifs_smb3_do_mount() ctx
@ 2021-04-22 22:14 David Disseldorp
2021-04-22 22:16 ` ronnie sahlberg
2021-04-22 22:35 ` Paulo Alcantara
0 siblings, 2 replies; 4+ messages in thread
From: David Disseldorp @ 2021-04-22 22:14 UTC (permalink / raw)
To: linux-cifs; +Cc: David Disseldorp
cifs_smb3_do_mount() calls smb3_fs_context_dup() and then
cifs_setup_volume_info(). The latter's subsequent smb3_parse_devname()
call overwrites the cifs_sb->ctx->UNC string already dup'ed by
smb3_fs_context_dup(), resulting in a leak. E.g.
unreferenced object 0xffff888002980420 (size 32):
comm "mount", pid 160, jiffies 4294892541 (age 30.416s)
hex dump (first 32 bytes):
5c 5c 31 39 32 2e 31 36 38 2e 31 37 34 2e 31 30 \\192.168.174.10
34 5c 72 61 70 69 64 6f 2d 73 68 61 72 65 00 00 4\rapido-share..
backtrace:
[<00000000069e12f6>] kstrdup+0x28/0x50
[<00000000b61f4032>] smb3_fs_context_dup+0x127/0x1d0 [cifs]
[<00000000c6e3e3bf>] cifs_smb3_do_mount+0x77/0x660 [cifs]
[<0000000063467a6b>] smb3_get_tree+0xdf/0x220 [cifs]
[<00000000716f731e>] vfs_get_tree+0x1b/0x90
[<00000000491d3892>] path_mount+0x62a/0x910
[<0000000046b2e774>] do_mount+0x50/0x70
[<00000000ca7b64dd>] __x64_sys_mount+0x81/0xd0
[<00000000b5122496>] do_syscall_64+0x33/0x40
[<000000002dd397af>] entry_SYSCALL_64_after_hwframe+0x44/0xae
This change is a bandaid until the cifs_setup_volume_info() TODO and
error handling issues are resolved.
Signed-off-by: David Disseldorp <ddiss@suse.de>
---
fs/cifs/cifsfs.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 5ddd20b62484..34c125798ad3 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -834,6 +834,12 @@ cifs_smb3_do_mount(struct file_system_type *fs_type,
goto out;
}
+ /* cifs_setup_volume_info->smb3_parse_devname() redups UNC & prepath */
+ kfree(cifs_sb->ctx->UNC);
+ cifs_sb->ctx->UNC = NULL;
+ kfree(cifs_sb->ctx->prepath);
+ cifs_sb->ctx->prepath = NULL;
+
rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, old_ctx->UNC);
if (rc) {
root = ERR_PTR(rc);
--
2.26.2
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] cifs: fix leak in cifs_smb3_do_mount() ctx
2021-04-22 22:14 [PATCH] cifs: fix leak in cifs_smb3_do_mount() ctx David Disseldorp
@ 2021-04-22 22:16 ` ronnie sahlberg
2021-04-22 22:35 ` Paulo Alcantara
1 sibling, 0 replies; 4+ messages in thread
From: ronnie sahlberg @ 2021-04-22 22:16 UTC (permalink / raw)
To: David Disseldorp; +Cc: linux-cifs
Acked-by me
On Fri, Apr 23, 2021 at 8:14 AM David Disseldorp <ddiss@suse.de> wrote:
>
> cifs_smb3_do_mount() calls smb3_fs_context_dup() and then
> cifs_setup_volume_info(). The latter's subsequent smb3_parse_devname()
> call overwrites the cifs_sb->ctx->UNC string already dup'ed by
> smb3_fs_context_dup(), resulting in a leak. E.g.
>
> unreferenced object 0xffff888002980420 (size 32):
> comm "mount", pid 160, jiffies 4294892541 (age 30.416s)
> hex dump (first 32 bytes):
> 5c 5c 31 39 32 2e 31 36 38 2e 31 37 34 2e 31 30 \\192.168.174.10
> 34 5c 72 61 70 69 64 6f 2d 73 68 61 72 65 00 00 4\rapido-share..
> backtrace:
> [<00000000069e12f6>] kstrdup+0x28/0x50
> [<00000000b61f4032>] smb3_fs_context_dup+0x127/0x1d0 [cifs]
> [<00000000c6e3e3bf>] cifs_smb3_do_mount+0x77/0x660 [cifs]
> [<0000000063467a6b>] smb3_get_tree+0xdf/0x220 [cifs]
> [<00000000716f731e>] vfs_get_tree+0x1b/0x90
> [<00000000491d3892>] path_mount+0x62a/0x910
> [<0000000046b2e774>] do_mount+0x50/0x70
> [<00000000ca7b64dd>] __x64_sys_mount+0x81/0xd0
> [<00000000b5122496>] do_syscall_64+0x33/0x40
> [<000000002dd397af>] entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> This change is a bandaid until the cifs_setup_volume_info() TODO and
> error handling issues are resolved.
>
> Signed-off-by: David Disseldorp <ddiss@suse.de>
> ---
> fs/cifs/cifsfs.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> index 5ddd20b62484..34c125798ad3 100644
> --- a/fs/cifs/cifsfs.c
> +++ b/fs/cifs/cifsfs.c
> @@ -834,6 +834,12 @@ cifs_smb3_do_mount(struct file_system_type *fs_type,
> goto out;
> }
>
> + /* cifs_setup_volume_info->smb3_parse_devname() redups UNC & prepath */
> + kfree(cifs_sb->ctx->UNC);
> + cifs_sb->ctx->UNC = NULL;
> + kfree(cifs_sb->ctx->prepath);
> + cifs_sb->ctx->prepath = NULL;
> +
> rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, old_ctx->UNC);
> if (rc) {
> root = ERR_PTR(rc);
> --
> 2.26.2
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] cifs: fix leak in cifs_smb3_do_mount() ctx
2021-04-22 22:14 [PATCH] cifs: fix leak in cifs_smb3_do_mount() ctx David Disseldorp
2021-04-22 22:16 ` ronnie sahlberg
@ 2021-04-22 22:35 ` Paulo Alcantara
2021-04-23 23:51 ` Steve French
1 sibling, 1 reply; 4+ messages in thread
From: Paulo Alcantara @ 2021-04-22 22:35 UTC (permalink / raw)
To: David Disseldorp, linux-cifs; +Cc: David Disseldorp
David Disseldorp <ddiss@suse.de> writes:
> cifs_smb3_do_mount() calls smb3_fs_context_dup() and then
> cifs_setup_volume_info(). The latter's subsequent smb3_parse_devname()
> call overwrites the cifs_sb->ctx->UNC string already dup'ed by
> smb3_fs_context_dup(), resulting in a leak. E.g.
>
> unreferenced object 0xffff888002980420 (size 32):
> comm "mount", pid 160, jiffies 4294892541 (age 30.416s)
> hex dump (first 32 bytes):
> 5c 5c 31 39 32 2e 31 36 38 2e 31 37 34 2e 31 30 \\192.168.174.10
> 34 5c 72 61 70 69 64 6f 2d 73 68 61 72 65 00 00 4\rapido-share..
> backtrace:
> [<00000000069e12f6>] kstrdup+0x28/0x50
> [<00000000b61f4032>] smb3_fs_context_dup+0x127/0x1d0 [cifs]
> [<00000000c6e3e3bf>] cifs_smb3_do_mount+0x77/0x660 [cifs]
> [<0000000063467a6b>] smb3_get_tree+0xdf/0x220 [cifs]
> [<00000000716f731e>] vfs_get_tree+0x1b/0x90
> [<00000000491d3892>] path_mount+0x62a/0x910
> [<0000000046b2e774>] do_mount+0x50/0x70
> [<00000000ca7b64dd>] __x64_sys_mount+0x81/0xd0
> [<00000000b5122496>] do_syscall_64+0x33/0x40
> [<000000002dd397af>] entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> This change is a bandaid until the cifs_setup_volume_info() TODO and
> error handling issues are resolved.
>
> Signed-off-by: David Disseldorp <ddiss@suse.de>
> ---
> fs/cifs/cifsfs.c | 6 ++++++
> 1 file changed, 6 insertions(+)
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] cifs: fix leak in cifs_smb3_do_mount() ctx
2021-04-22 22:35 ` Paulo Alcantara
@ 2021-04-23 23:51 ` Steve French
0 siblings, 0 replies; 4+ messages in thread
From: Steve French @ 2021-04-23 23:51 UTC (permalink / raw)
To: Paulo Alcantara; +Cc: David Disseldorp, CIFS
merged into cifs-2.6.git for-next and kicking off (buildbot) testing
run with it now
On Thu, Apr 22, 2021 at 5:36 PM Paulo Alcantara <pc@cjr.nz> wrote:
>
> David Disseldorp <ddiss@suse.de> writes:
>
> > cifs_smb3_do_mount() calls smb3_fs_context_dup() and then
> > cifs_setup_volume_info(). The latter's subsequent smb3_parse_devname()
> > call overwrites the cifs_sb->ctx->UNC string already dup'ed by
> > smb3_fs_context_dup(), resulting in a leak. E.g.
> >
> > unreferenced object 0xffff888002980420 (size 32):
> > comm "mount", pid 160, jiffies 4294892541 (age 30.416s)
> > hex dump (first 32 bytes):
> > 5c 5c 31 39 32 2e 31 36 38 2e 31 37 34 2e 31 30 \\192.168.174.10
> > 34 5c 72 61 70 69 64 6f 2d 73 68 61 72 65 00 00 4\rapido-share..
> > backtrace:
> > [<00000000069e12f6>] kstrdup+0x28/0x50
> > [<00000000b61f4032>] smb3_fs_context_dup+0x127/0x1d0 [cifs]
> > [<00000000c6e3e3bf>] cifs_smb3_do_mount+0x77/0x660 [cifs]
> > [<0000000063467a6b>] smb3_get_tree+0xdf/0x220 [cifs]
> > [<00000000716f731e>] vfs_get_tree+0x1b/0x90
> > [<00000000491d3892>] path_mount+0x62a/0x910
> > [<0000000046b2e774>] do_mount+0x50/0x70
> > [<00000000ca7b64dd>] __x64_sys_mount+0x81/0xd0
> > [<00000000b5122496>] do_syscall_64+0x33/0x40
> > [<000000002dd397af>] entry_SYSCALL_64_after_hwframe+0x44/0xae
> >
> > This change is a bandaid until the cifs_setup_volume_info() TODO and
> > error handling issues are resolved.
> >
> > Signed-off-by: David Disseldorp <ddiss@suse.de>
> > ---
> > fs/cifs/cifsfs.c | 6 ++++++
> > 1 file changed, 6 insertions(+)
>
> Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
--
Thanks,
Steve
^ permalink raw reply [flat|nested] 4+ messages in thread
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2021-04-22 22:14 [PATCH] cifs: fix leak in cifs_smb3_do_mount() ctx David Disseldorp
2021-04-22 22:16 ` ronnie sahlberg
2021-04-22 22:35 ` Paulo Alcantara
2021-04-23 23:51 ` Steve French
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