* [PATCH] x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task
@ 2020-08-14 18:16 Eric Dumazet
2020-08-14 19:03 ` Andy Lutomirski
2020-08-15 11:48 ` Ingo Molnar
0 siblings, 2 replies; 6+ messages in thread
From: Eric Dumazet @ 2020-08-14 18:16 UTC (permalink / raw)
To: Ingo Molnar
Cc: linux-kernel, Eric Dumazet, Eric Dumazet, Jann Horn, syzbot,
Andy Lutomirski, Chang S . Bae, Andy Lutomirski, Borislav Petkov,
Brian Gerst, Dave Hansen, Denys Vlasenko, H . Peter Anvin,
Linus Torvalds, Markus T Metzger, Peter Zijlstra, Ravi Shankar,
Rik van Riel, Thomas Gleixner
syzbot found its way in 86_fsgsbase_read_task() [1]
Fix is to make sure ldt pointer is not NULL.
[1]
general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 PID: 6866 Comm: syz-executor262 Not tainted 5.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:x86_fsgsbase_read_task+0x16d/0x310 arch/x86/kernel/process_64.c:393
Code: 3c 02 00 0f 85 7c 01 00 00 4c 8b a5 80 04 00 00 44 0f b7 eb 48 b8 00 00 00 00 00 fc ff df 49 8d 7c 24 08 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 30 01 00 00 45 3b 6c 24 08 0f
RSP: 0018:ffffc90001677db8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000008 RDI: 0000000000000008
RBP: ffff88809eaf9780 R08: 0000000000000000 R09: ffff88809eaf9c17
R10: ffffed1013d5f382 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000020000080
FS: 0000000000000000(0000) GS:ffff8880ae600000(0063) knlGS:0000000009cf4840
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000020000080 CR3: 000000009fa0d000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
putreg32+0x3ab/0x530 arch/x86/kernel/ptrace.c:876
genregs32_set arch/x86/kernel/ptrace.c:1026 [inline]
genregs32_set+0xa4/0x100 arch/x86/kernel/ptrace.c:1006
copy_regset_from_user include/linux/regset.h:326 [inline]
ia32_arch_ptrace arch/x86/kernel/ptrace.c:1061 [inline]
compat_arch_ptrace+0x36c/0xd90 arch/x86/kernel/ptrace.c:1198
__do_compat_sys_ptrace kernel/ptrace.c:1420 [inline]
__se_compat_sys_ptrace kernel/ptrace.c:1389 [inline]
__ia32_compat_sys_ptrace+0x220/0x2f0 kernel/ptrace.c:1389
do_syscall_32_irqs_on arch/x86/entry/common.c:84 [inline]
__do_fast_syscall_32+0x57/0x80 arch/x86/entry/common.c:126
do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:149
entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7fe9569
Code: 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000ffd99e7c EFLAGS: 00000217 ORIG_RAX: 000000000000001a
RAX: ffffffffffffffda RBX: 000000000000000d RCX: 0000000000001ad1
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000001ad1
RBP: 000000000000003c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace f79c8042700af7c5 ]---
RIP: 0010:x86_fsgsbase_read_task+0x16d/0x310 arch/x86/kernel/process_64.c:393
Code: 3c 02 00 0f 85 7c 01 00 00 4c 8b a5 80 04 00 00 44 0f b7 eb 48 b8 00 00 00 00 00 fc ff df 49 8d 7c 24 08 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 30 01 00 00 45 3b 6c 24 08 0f
RSP: 0018:ffffc90001677db8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000008 RDI: 0000000000000008
RBP: ffff88809eaf9780 R08: 0000000000000000 R09: ffff88809eaf9c17
R10: ffffed1013d5f382 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000020000080
FS: 0000000000000000(0000) GS:ffff8880ae600000(0063) knlGS:0000000009cf4840
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000020000080 CR3: 000000009fa0d000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Fixes: 07e1d88adaae ("x86/fsgsbase/64: Fix ptrace() to read the FS/GS base accurately")
Co-developed-by: Jann Horn <jannh@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Chang S. Bae <chang.seok.bae@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Markus T Metzger <markus.t.metzger@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/process_64.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index d6f946707270e41d4aa04e4069b1b4eb82afd687..8393ee1aa9c89b3712b7aef510149d73762ef314 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -390,7 +390,7 @@ unsigned long x86_fsgsbase_read_task(struct task_struct *task,
*/
mutex_lock(&task->mm->context.lock);
ldt = task->mm->context.ldt;
- if (unlikely(idx >= ldt->nr_entries))
+ if (unlikely(ldt == NULL || idx >= ldt->nr_entries))
base = 0;
else
base = get_desc_base(ldt->entries + idx);
--
2.28.0.220.ged08abb693-goog
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task 2020-08-14 18:16 [PATCH] x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task Eric Dumazet @ 2020-08-14 19:03 ` Andy Lutomirski 2020-08-14 19:12 ` Eric Dumazet 2020-08-14 19:37 ` Jann Horn 2020-08-15 11:48 ` Ingo Molnar 1 sibling, 2 replies; 6+ messages in thread From: Andy Lutomirski @ 2020-08-14 19:03 UTC (permalink / raw) To: Eric Dumazet Cc: Ingo Molnar, linux-kernel, Eric Dumazet, Jann Horn, syzbot, Andy Lutomirski, Chang S . Bae, Borislav Petkov, Brian Gerst, Dave Hansen, Denys Vlasenko, H . Peter Anvin, Linus Torvalds, Markus T Metzger, Peter Zijlstra, Ravi Shankar, Rik van Riel, Thomas Gleixner > On Aug 14, 2020, at 11:16 AM, Eric Dumazet <edumazet@google.com> wrote: > > syzbot found its way in 86_fsgsbase_read_task() [1] > > Fix is to make sure ldt pointer is not NULL Acked-by: Andy Lutomirski <luto@kernel.org> Maybe add something like this to the changelog: This can happen if ptrace() or sigreturn() pokes an LDT selector into FS or GS for a task with no LDT and something tries to read the base before a return to usermode notices the bad selector and fixes it. I’ll see if I can whip up a test case too. > > [1] > general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN > KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] > CPU: 0 PID: 6866 Comm: syz-executor262 Not tainted 5.8.0-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > RIP: 0010:x86_fsgsbase_read_task+0x16d/0x310 arch/x86/kernel/process_64.c:393 > Code: 3c 02 00 0f 85 7c 01 00 00 4c 8b a5 80 04 00 00 44 0f b7 eb 48 b8 00 00 00 00 00 fc ff df 49 8d 7c 24 08 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 30 01 00 00 45 3b 6c 24 08 0f > RSP: 0018:ffffc90001677db8 EFLAGS: 00010202 > RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 > RDX: 0000000000000001 RSI: 0000000000000008 RDI: 0000000000000008 > RBP: ffff88809eaf9780 R08: 0000000000000000 R09: ffff88809eaf9c17 > R10: ffffed1013d5f382 R11: 0000000000000000 R12: 0000000000000000 > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000020000080 > FS: 0000000000000000(0000) GS:ffff8880ae600000(0063) knlGS:0000000009cf4840 > CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 > CR2: 0000000020000080 CR3: 000000009fa0d000 CR4: 00000000001506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > putreg32+0x3ab/0x530 arch/x86/kernel/ptrace.c:876 > genregs32_set arch/x86/kernel/ptrace.c:1026 [inline] > genregs32_set+0xa4/0x100 arch/x86/kernel/ptrace.c:1006 > copy_regset_from_user include/linux/regset.h:326 [inline] > ia32_arch_ptrace arch/x86/kernel/ptrace.c:1061 [inline] > compat_arch_ptrace+0x36c/0xd90 arch/x86/kernel/ptrace.c:1198 > __do_compat_sys_ptrace kernel/ptrace.c:1420 [inline] > __se_compat_sys_ptrace kernel/ptrace.c:1389 [inline] > __ia32_compat_sys_ptrace+0x220/0x2f0 kernel/ptrace.c:1389 > do_syscall_32_irqs_on arch/x86/entry/common.c:84 [inline] > __do_fast_syscall_32+0x57/0x80 arch/x86/entry/common.c:126 > do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:149 > entry_SYSENTER_compat_after_hwframe+0x4d/0x5c > RIP: 0023:0xf7fe9569 > Code: 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 > RSP: 002b:00000000ffd99e7c EFLAGS: 00000217 ORIG_RAX: 000000000000001a > RAX: ffffffffffffffda RBX: 000000000000000d RCX: 0000000000001ad1 > RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000001ad1 > RBP: 000000000000003c R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 > Modules linked in: > ---[ end trace f79c8042700af7c5 ]--- > RIP: 0010:x86_fsgsbase_read_task+0x16d/0x310 arch/x86/kernel/process_64.c:393 > Code: 3c 02 00 0f 85 7c 01 00 00 4c 8b a5 80 04 00 00 44 0f b7 eb 48 b8 00 00 00 00 00 fc ff df 49 8d 7c 24 08 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 30 01 00 00 45 3b 6c 24 08 0f > RSP: 0018:ffffc90001677db8 EFLAGS: 00010202 > RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 > RDX: 0000000000000001 RSI: 0000000000000008 RDI: 0000000000000008 > RBP: ffff88809eaf9780 R08: 0000000000000000 R09: ffff88809eaf9c17 > R10: ffffed1013d5f382 R11: 0000000000000000 R12: 0000000000000000 > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000020000080 > FS: 0000000000000000(0000) GS:ffff8880ae600000(0063) knlGS:0000000009cf4840 > CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 > CR2: 0000000020000080 CR3: 000000009fa0d000 CR4: 00000000001506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Fixes: 07e1d88adaae ("x86/fsgsbase/64: Fix ptrace() to read the FS/GS base accurately") > Co-developed-by: Jann Horn <jannh@google.com> > Signed-off-by: Eric Dumazet <edumazet@google.com> > Reported-by: syzbot <syzkaller@googlegroups.com> > Cc: Andy Lutomirski <luto@kernel.org> > Cc: Chang S. Bae <chang.seok.bae@intel.com> > Cc: Andy Lutomirski <luto@amacapital.net> > Cc: Borislav Petkov <bp@alien8.de> > Cc: Brian Gerst <brgerst@gmail.com> > Cc: Dave Hansen <dave.hansen@linux.intel.com> > Cc: Denys Vlasenko <dvlasenk@redhat.com> > Cc: H. Peter Anvin <hpa@zytor.com> > Cc: Linus Torvalds <torvalds@linux-foundation.org> > Cc: Markus T Metzger <markus.t.metzger@intel.com> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Ravi Shankar <ravi.v.shankar@intel.com> > Cc: Rik van Riel <riel@surriel.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Ingo Molnar <mingo@kernel.org> > --- > arch/x86/kernel/process_64.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c > index d6f946707270e41d4aa04e4069b1b4eb82afd687..8393ee1aa9c89b3712b7aef510149d73762ef314 100644 > --- a/arch/x86/kernel/process_64.c > +++ b/arch/x86/kernel/process_64.c > @@ -390,7 +390,7 @@ unsigned long x86_fsgsbase_read_task(struct task_struct *task, > */ > mutex_lock(&task->mm->context.lock); > ldt = task->mm->context.ldt; > - if (unlikely(idx >= ldt->nr_entries)) > + if (unlikely(ldt == NULL || idx >= ldt->nr_entries)) > base = 0; > else > base = get_desc_base(ldt->entries + idx); > -- > 2.28.0.220.ged08abb693-goog > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task 2020-08-14 19:03 ` Andy Lutomirski @ 2020-08-14 19:12 ` Eric Dumazet 2020-08-14 19:37 ` Jann Horn 1 sibling, 0 replies; 6+ messages in thread From: Eric Dumazet @ 2020-08-14 19:12 UTC (permalink / raw) To: Andy Lutomirski Cc: Ingo Molnar, linux-kernel, Eric Dumazet, Jann Horn, syzbot, Andy Lutomirski, Chang S . Bae, Borislav Petkov, Brian Gerst, Dave Hansen, Denys Vlasenko, H . Peter Anvin, Linus Torvalds, Markus T Metzger, Peter Zijlstra, Ravi Shankar, Rik van Riel, Thomas Gleixner On Fri, Aug 14, 2020 at 12:03 PM Andy Lutomirski <luto@amacapital.net> wrote: > > > > > On Aug 14, 2020, at 11:16 AM, Eric Dumazet <edumazet@google.com> wrote: > > > > syzbot found its way in 86_fsgsbase_read_task() [1] > > > > Fix is to make sure ldt pointer is not NULL > > Acked-by: Andy Lutomirski <luto@kernel.org> > > Maybe add something like this to the changelog: > > This can happen if ptrace() or sigreturn() pokes an LDT selector into FS or GS for a task with no LDT and something tries to read the base before a return to usermode notices the bad selector and fixes it. > > I’ll see if I can whip up a test case too. > Jann has a repro if needed (and syzbot also had one) ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task 2020-08-14 19:03 ` Andy Lutomirski 2020-08-14 19:12 ` Eric Dumazet @ 2020-08-14 19:37 ` Jann Horn 1 sibling, 0 replies; 6+ messages in thread From: Jann Horn @ 2020-08-14 19:37 UTC (permalink / raw) To: Andy Lutomirski Cc: Eric Dumazet, Ingo Molnar, linux-kernel, Eric Dumazet, syzbot, Andy Lutomirski, Chang S . Bae, Borislav Petkov, Brian Gerst, Dave Hansen, Denys Vlasenko, H . Peter Anvin, Linus Torvalds, Markus T Metzger, Peter Zijlstra, Ravi Shankar, Rik van Riel, Thomas Gleixner On Fri, Aug 14, 2020 at 9:03 PM Andy Lutomirski <luto@amacapital.net> wrote: > > On Aug 14, 2020, at 11:16 AM, Eric Dumazet <edumazet@google.com> wrote: > > > > syzbot found its way in 86_fsgsbase_read_task() [1] > > > > Fix is to make sure ldt pointer is not NULL > > Acked-by: Andy Lutomirski <luto@kernel.org> > > Maybe add something like this to the changelog: > > This can happen if ptrace() or sigreturn() pokes an LDT selector into FS or GS for a task with no LDT and something tries to read the base before a return to usermode notices the bad selector and fixes it. > > I’ll see if I can whip up a test case too. This is the reproducer I used to test this on 4.20.17: #include <stdio.h> #include <unistd.h> #include <err.h> #include <sys/wait.h> #include <sys/ptrace.h> #include <sys/user.h> #include <sys/prctl.h> #include <signal.h> #include <stddef.h> #include <errno.h> #define SEL_LDT 0x4 #define USER_RPL 0x3 #define LDT_SELECTOR(idx) (((idx)<<3) | SEL_LDT | USER_RPL) int main(void) { pid_t child = fork(); if (child == -1) err(1, "fork"); if (child == 0) { prctl(PR_SET_PDEATHSIG, SIGKILL); while (1) pause(); } if (ptrace(PTRACE_ATTACH, child, NULL, NULL)) err(1, "PTRACE_ATTACH"); int status; if (waitpid(child, &status, __WALL) != child) err(1, "waitpid"); if (ptrace( PTRACE_POKEUSER, child, (void*)offsetof(struct user_regs_struct, fs), (void*)LDT_SELECTOR(0) )) err(1, "PTRACE_POKEUSER"); errno = 0; unsigned long val = ptrace( PTRACE_PEEKUSER, child, (void*)offsetof(struct user_regs_struct, fs_base), NULL ); printf("PTRACE_PEEKUSER returns user_regs_struct.fs_base = 0x%lx (%m)\n", val); } ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task 2020-08-14 18:16 [PATCH] x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task Eric Dumazet 2020-08-14 19:03 ` Andy Lutomirski @ 2020-08-15 11:48 ` Ingo Molnar 2020-08-15 17:38 ` Eric Dumazet 1 sibling, 1 reply; 6+ messages in thread From: Ingo Molnar @ 2020-08-15 11:48 UTC (permalink / raw) To: Eric Dumazet Cc: linux-kernel, Eric Dumazet, Jann Horn, syzbot, Andy Lutomirski, Chang S . Bae, Andy Lutomirski, Borislav Petkov, Brian Gerst, Dave Hansen, Denys Vlasenko, H . Peter Anvin, Linus Torvalds, Markus T Metzger, Peter Zijlstra, Ravi Shankar, Rik van Riel, Thomas Gleixner * Eric Dumazet <edumazet@google.com> wrote: > syzbot found its way in 86_fsgsbase_read_task() [1] > > Fix is to make sure ldt pointer is not NULL. Thanks for this fix. Linus has picked it up (inclusive the typos to the x86_fsgsbase_read_task() function name ;-), it's now upstream under: 8ab49526b53d: ("x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task") By the fixes tag it looks like this should probably be backported all the way back to ~v4.20 or so? Thanks, Ingo ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task 2020-08-15 11:48 ` Ingo Molnar @ 2020-08-15 17:38 ` Eric Dumazet 0 siblings, 0 replies; 6+ messages in thread From: Eric Dumazet @ 2020-08-15 17:38 UTC (permalink / raw) To: Ingo Molnar Cc: linux-kernel, Eric Dumazet, Jann Horn, syzbot, Andy Lutomirski, Chang S . Bae, Andy Lutomirski, Borislav Petkov, Brian Gerst, Dave Hansen, Denys Vlasenko, H . Peter Anvin, Linus Torvalds, Markus T Metzger, Peter Zijlstra, Ravi Shankar, Rik van Riel, Thomas Gleixner On Sat, Aug 15, 2020 at 4:48 AM Ingo Molnar <mingo@kernel.org> wrote: > > > * Eric Dumazet <edumazet@google.com> wrote: > > > syzbot found its way in 86_fsgsbase_read_task() [1] > > > > Fix is to make sure ldt pointer is not NULL. > > Thanks for this fix. Linus has picked it up (inclusive the typos to > the x86_fsgsbase_read_task() function name ;-), it's now upstream > under: > > 8ab49526b53d: ("x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task") > > By the fixes tag it looks like this should probably be backported all > the way back to ~v4.20 or so? This is absolutely right, sorry about the lack of a stable tag. Most of my patches usually land into David Miller trees, where the stable tag is not welcomed. We use Fixes: tags to convey the exact information needed for stable backports. Thanks. ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-08-15 21:59 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-08-14 18:16 [PATCH] x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task Eric Dumazet 2020-08-14 19:03 ` Andy Lutomirski 2020-08-14 19:12 ` Eric Dumazet 2020-08-14 19:37 ` Jann Horn 2020-08-15 11:48 ` Ingo Molnar 2020-08-15 17:38 ` Eric Dumazet
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