diff options
| author | Rasmus Villemoes <linux@rasmusvillemoes.dk> | 2013-07-08 15:59:48 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-07-09 10:33:20 -0700 |
| commit | 9a2458a633d4b3c9e0eae506da40cf44dc075314 (patch) | |
| tree | 6212adc65070486edc212587c8f3a16452d810ec | |
| parent | 34e3a58c66aafd90cc16c061569fbefc3ff451e9 (diff) | |
| download | lwn-9a2458a633d4b3c9e0eae506da40cf44dc075314.tar.gz lwn-9a2458a633d4b3c9e0eae506da40cf44dc075314.zip | |
mm: mremap: validate input before taking lock
This patch is very similar to commit 84d96d897671 ("mm: madvise:
complete input validation before taking lock"): perform some basic
validation of the input to mremap() before taking the
¤t->mm->mmap_sem lock.
This also makes the MREMAP_FIXED => MREMAP_MAYMOVE dependency slightly
more explicit.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/mremap.c | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/mm/mremap.c b/mm/mremap.c index 3708655378e9..457d34ef3bf2 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -456,13 +456,14 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, unsigned long charged = 0; bool locked = false; - down_write(¤t->mm->mmap_sem); - if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE)) - goto out; + return ret; + + if (flags & MREMAP_FIXED && !(flags & MREMAP_MAYMOVE)) + return ret; if (addr & ~PAGE_MASK) - goto out; + return ret; old_len = PAGE_ALIGN(old_len); new_len = PAGE_ALIGN(new_len); @@ -473,12 +474,13 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, * a zero new-len is nonsensical. */ if (!new_len) - goto out; + return ret; + + down_write(¤t->mm->mmap_sem); if (flags & MREMAP_FIXED) { - if (flags & MREMAP_MAYMOVE) - ret = mremap_to(addr, old_len, new_addr, new_len, - &locked); + ret = mremap_to(addr, old_len, new_addr, new_len, + &locked); goto out; } |