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x86: shadow stacks: proper error handling for mmap lock

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김영민 reports that shstk_pop_sigframe() doesn't check for errors from
mmap_read_lock_killable(), which is a silly oversight, and also shows
that we haven't marked those functions with "__must_check", which would
have immediately caught it.

So let's fix both issues.

Reported-by: 김영민 <osori@hspace.io>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds
2026-04-08 13:18:57 -07:00
parent 3036cd0d33
commit 52f657e34d
2 changed files with 5 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
arch/x86/kernel/shstk.c
View File

@@ -351,7 +351,8 @@ static int shstk_pop_sigframe(unsigned long *ssp)
need_to_check_vma = PAGE_ALIGN(*ssp) == *ssp;
if (need_to_check_vma)
mmap_read_lock_killable(current->mm);
if (mmap_read_lock_killable(current->mm))
return -EINTR;
err = get_shstk_data(&token_addr, (unsigned long __user *)*ssp);
if (unlikely(err))

6
include/linux/mmap_lock.h
View File

@@ -546,7 +546,7 @@ static inline void mmap_write_lock_nested(struct mm_struct *mm, int subclass)
__mmap_lock_trace_acquire_returned(mm, true, true);
}
static inline int mmap_write_lock_killable(struct mm_struct *mm)
static inline int __must_check mmap_write_lock_killable(struct mm_struct *mm)
{
int ret;
@@ -593,7 +593,7 @@ static inline void mmap_read_lock(struct mm_struct *mm)
__mmap_lock_trace_acquire_returned(mm, false, true);
}
static inline int mmap_read_lock_killable(struct mm_struct *mm)
static inline int __must_check mmap_read_lock_killable(struct mm_struct *mm)
{
int ret;
@@ -603,7 +603,7 @@ static inline int mmap_read_lock_killable(struct mm_struct *mm)
return ret;
}
static inline bool mmap_read_trylock(struct mm_struct *mm)
static inline bool __must_check mmap_read_trylock(struct mm_struct *mm)
{
bool ret;