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| author | Daniel Micay <danielmicay@gmail.com> | 2017-05-22 04:56:22 -0400 |
|---|---|---|
| committer | Moyster <oysterized@gmail.com> | 2018-05-16 13:26:07 +0200 |
| commit | 617387d117b60601979b49c8aa98b8e8e840c446 (patch) | |
| tree | 78a71aaef11466c435b96284a1e0be97b76ea541 | |
| parent | c8972edb1a80b6395f9df64f6ea856cd09e334e3 (diff) | |
arm64: properly account for stack rnd in mmap base
The stack ASLR base was not included in the gap size for rlimit values
larger than MIN_GAP, resulting in insufficient space being reserved.
PaX uses an alternate approach where the mmap base is instead offset
from the actual random stack base, but this works for the time being.
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
| -rw-r--r-- | arch/arm64/mm/mmap.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c index 8f6bcc3f4..5a07020b8 100644 --- a/arch/arm64/mm/mmap.c +++ b/arch/arm64/mm/mmap.c @@ -33,7 +33,7 @@ * Leave enough space between the mmap area and the stack to honour ulimit in * the face of randomisation. */ -#define MIN_GAP (SZ_128M + ((STACK_RND_MASK << PAGE_SHIFT) + 1)) +#define MIN_GAP (SZ_128M) #define MAX_GAP (STACK_TOP/6*5) static int mmap_is_legacy(void) @@ -65,6 +65,9 @@ static unsigned long mmap_rnd(void) static unsigned long mmap_base(void) { unsigned long gap = rlimit(RLIMIT_STACK); + unsigned long pad = STACK_RND_MASK << PAGE_SHIFT; + if (gap + pad > gap) + gap += pad; if (gap < MIN_GAP) gap = MIN_GAP; |