diff options
| author | Vincent Fazio | 2021-01-31 07:18:49 +0100 |
|---|---|---|
| committer | Laurent Vivier | 2021-03-13 10:45:11 +0100 |
| commit | 7e588fbc57397daac02cf23677d1849aab7c7507 (patch) | |
| tree | 37a98faff2e2a1c1a92266e6f5c1dc8686726bbb | |
| parent | linux-user: manage binfmt-misc preserve-arg[0] flag (diff) | |
| download | qemu-7e588fbc57397daac02cf23677d1849aab7c7507.tar.gz qemu-7e588fbc57397daac02cf23677d1849aab7c7507.tar.xz qemu-7e588fbc57397daac02cf23677d1849aab7c7507.zip | |
linux-user/elfload: munmap proper address in pgd_find_hole_fallback
Previously, if the build host's libc did not define MAP_FIXED_NOREPLACE
or if the running kernel didn't support that flag, it was possible for
pgd_find_hole_fallback to munmap an incorrect address which could lead to
SIGSEGV if the range happened to overlap with the mapped address of the
QEMU binary.
mmap(0x1000, 22261224, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, -1, 0) = 0x7f889d331000
munmap(0x1000, 22261224) = 0
--- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_MAPERR, si_addr=0x84b817} ---
++ killed by SIGSEGV +++
Now, always munmap the address returned by mmap.
Fixes: 2667e069e7b5 ("linux-user: don't use MAP_FIXED in pgd_find_hole_fallback")
Signed-off-by: Vincent Fazio <vfazio@gmail.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210131061849.12615-1-vfazio@xes-inc.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
| -rw-r--r-- | linux-user/elfload.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 140a971632..174ee7bad6 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -2209,7 +2209,7 @@ static uintptr_t pgd_find_hole_fallback(uintptr_t guest_size, uintptr_t brk, void * mmap_start = mmap((void *) align_start, guest_size, PROT_NONE, flags, -1, 0); if (mmap_start != MAP_FAILED) { - munmap((void *) align_start, guest_size); + munmap(mmap_start, guest_size); if (MAP_FIXED_NOREPLACE != 0 || mmap_start == (void *) align_start) { return (uintptr_t) mmap_start + offset; |