diff options
| author | Ludwig Nussel <ludwig.nussel@suse.de> | 2011-11-15 14:46:46 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2012-01-25 17:24:43 -0800 |
| commit | 59c43b2c3ef410e585646825ea552507cd51ccb1 (patch) | |
| tree | a3841562c5bb1ee5aaa3244b3c250528d5c6cdcc /arch | |
| parent | ea1c62778121f6ece5e0120250716b45e204cb13 (diff) | |
| download | lwn-59c43b2c3ef410e585646825ea552507cd51ccb1.tar.gz lwn-59c43b2c3ef410e585646825ea552507cd51ccb1.zip | |
x86: Fix mmap random address range
commit 9af0c7a6fa860698d080481f24a342ba74b68982 upstream.
On x86_32 casting the unsigned int result of get_random_int() to
long may result in a negative value. On x86_32 the range of
mmap_rnd() therefore was -255 to 255. The 32bit mode on x86_64
used 0 to 255 as intended.
The bug was introduced by 675a081 ("x86: unify mmap_{32|64}.c")
in January 2008.
Signed-off-by: Ludwig Nussel <ludwig.nussel@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: harvey.harrison@gmail.com
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/201111152246.pAFMklOB028527@wpaz5.hot.corp.google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/mm/mmap.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c index 1dab5194fd9d..f927429d07ca 100644 --- a/arch/x86/mm/mmap.c +++ b/arch/x86/mm/mmap.c @@ -87,9 +87,9 @@ static unsigned long mmap_rnd(void) */ if (current->flags & PF_RANDOMIZE) { if (mmap_is_ia32()) - rnd = (long)get_random_int() % (1<<8); + rnd = get_random_int() % (1<<8); else - rnd = (long)(get_random_int() % (1<<28)); + rnd = get_random_int() % (1<<28); } return rnd << PAGE_SHIFT; } |