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| author | Larry Woodman <lwoodman@redhat.com> | 2010-09-24 12:04:48 -0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-09-25 09:34:58 -0700 |
| commit | 5ec1055aa5632dd7a8283cdb5fa9be3c535eaa06 (patch) | |
| tree | 231fa9a989433ee7fab796342f7ebc2c3e167342 /mm/fremap.c | |
| parent | 8ae09259ffe2402e956efd5a36220b6161e9ecb3 (diff) | |
| download | lwn-5ec1055aa5632dd7a8283cdb5fa9be3c535eaa06.tar.gz lwn-5ec1055aa5632dd7a8283cdb5fa9be3c535eaa06.zip | |
Avoid pgoff overflow in remap_file_pages
Thomas Pollet noticed that the remap_file_pages() system call in
fremap.c has a potential overflow in the first part of the if statement
below, which could cause it to process bogus input parameters.
Specifically the pgoff + size parameters could be wrap thereby
preventing the system call from failing when it should.
Reported-by: Thomas Pollet <thomas.pollet@gmail.com>
Signed-off-by: Larry Woodman <lwoodman@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/fremap.c')
| -rw-r--r-- | mm/fremap.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/fremap.c b/mm/fremap.c index 7b7f852848de..ec520c7b28df 100644 --- a/mm/fremap.c +++ b/mm/fremap.c @@ -141,6 +141,10 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, if (start + size <= start) return err; + /* Does pgoff wrap? */ + if (pgoff + (size >> PAGE_SHIFT) < pgoff) + return err; + /* Can we represent this offset inside this architecture's pte's? */ #if PTE_FILE_MAX_BITS < BITS_PER_LONG if (pgoff + (size >> PAGE_SHIFT) >= (1UL << PTE_FILE_MAX_BITS)) |