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| author | Jason Gunthorpe <jgg@nvidia.com> | 2023-06-19 15:27:25 -0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-06-23 16:59:27 -0700 |
| commit | 9883c7f84053cec2826ca3c56254601b5ce9cdbe (patch) | |
| tree | dcdc7f4040b01975d20303c37de21d5be2f66828 /mm/gup.c | |
| parent | 0b52c420350e8f9873ba62768cd8246827184408 (diff) | |
| download | lwn-9883c7f84053cec2826ca3c56254601b5ce9cdbe.tar.gz lwn-9883c7f84053cec2826ca3c56254601b5ce9cdbe.zip | |
mm/gup: do not return 0 from pin_user_pages_fast() for bad args
These routines are not intended to return zero, the callers cannot do
anything sane with a 0 return. They should return an error which means
future calls to GUP will not succeed, or they should return some non-zero
number of pinned pages which means GUP should be called again.
If start + nr_pages overflows it should return -EOVERFLOW to signal the
arguments are invalid.
Syzkaller keeps tripping on this when fuzzing GUP arguments.
Link: https://lkml.kernel.org/r/0-v1-3d5ed1f20d50+104-gup_overflow_jgg@nvidia.com
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reported-by: syzbot+353c7be4964c6253f24a@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/000000000000094fdd05faa4d3a4@google.com
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/gup.c')
| -rw-r--r-- | mm/gup.c | 2 |
1 files changed, 1 insertions, 1 deletions
@@ -3080,7 +3080,7 @@ static int internal_get_user_pages_fast(unsigned long start, start = untagged_addr(start) & PAGE_MASK; len = nr_pages << PAGE_SHIFT; if (check_add_overflow(start, len, &end)) - return 0; + return -EOVERFLOW; if (end > TASK_SIZE_MAX) return -EFAULT; if (unlikely(!access_ok((void __user *)start, len))) |