diff options
| author | Alexey Dobriyan <adobriyan@gmail.com> | 2018-06-15 01:27:24 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-06-15 01:55:24 +0300 |
| commit | 86a2bb5ad83161cc687671bdf188699e137ae226 (patch) | |
| tree | 8556deca018ee7b44028d03bef993118b945d188 | |
| parent | c2574aaa5d98684519f0dfa64abe6896aeb124c6 (diff) | |
| download | linux-86a2bb5ad83161cc687671bdf188699e137ae226.tar.xz | |
coredump: fix spam with zero VMA process
Nobody ever tried to self destruct by unmapping whole address space at
once:
munmap((void *)0, (1ULL << 47) - 4096);
Doing this produces 2 warnings for zero-length vmalloc allocations:
a.out[1353]: segfault at 7f80bcc4b757 ip 00007f80bcc4b757 sp 00007fff683939b8 error 14
a.out: vmalloc: allocation failure: 0 bytes, mode:0xcc0(GFP_KERNEL), nodemask=(null)
...
a.out: vmalloc: allocation failure: 0 bytes, mode:0xcc0(GFP_KERNEL), nodemask=(null)
...
Fix is to switch to kvmalloc().
Steps to reproduce:
// vsyscall=none
#include <sys/mman.h>
#include <sys/resource.h>
int main(void)
{
setrlimit(RLIMIT_CORE, &(struct rlimit){RLIM_INFINITY, RLIM_INFINITY});
munmap((void *)0, (1ULL << 47) - 4096);
return 0;
}
Link: http://lkml.kernel.org/r/20180410180353.GA2515@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/binfmt_elf.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 070b6184642d..0ac456b52bdd 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1621,8 +1621,8 @@ static int fill_files_note(struct memelfnote *note) if (size >= MAX_FILE_NOTE_SIZE) /* paranoia check */ return -EINVAL; size = round_up(size, PAGE_SIZE); - data = vmalloc(size); - if (!data) + data = kvmalloc(size, GFP_KERNEL); + if (ZERO_OR_NULL_PTR(data)) return -ENOMEM; start_end_ofs = data + 2; @@ -1639,7 +1639,7 @@ static int fill_files_note(struct memelfnote *note) filename = file_path(file, name_curpos, remaining); if (IS_ERR(filename)) { if (PTR_ERR(filename) == -ENAMETOOLONG) { - vfree(data); + kvfree(data); size = size * 5 / 4; goto alloc; } @@ -1932,7 +1932,7 @@ static void free_note_info(struct elf_note_info *info) kfree(t); } kfree(info->psinfo.data); - vfree(info->files.data); + kvfree(info->files.data); } #else @@ -2148,7 +2148,7 @@ static void free_note_info(struct elf_note_info *info) /* Free data possibly allocated by fill_files_note(): */ if (info->notes_files) - vfree(info->notes_files->data); + kvfree(info->notes_files->data); kfree(info->prstatus); kfree(info->psinfo); @@ -2294,8 +2294,9 @@ static int elf_core_dump(struct coredump_params *cprm) if (segs - 1 > ULONG_MAX / sizeof(*vma_filesz)) goto end_coredump; - vma_filesz = vmalloc(array_size(sizeof(*vma_filesz), (segs - 1))); - if (!vma_filesz) + vma_filesz = kvmalloc(array_size(sizeof(*vma_filesz), (segs - 1)), + GFP_KERNEL); + if (ZERO_OR_NULL_PTR(vma_filesz)) goto end_coredump; for (i = 0, vma = first_vma(current, gate_vma); vma != NULL; @@ -2402,7 +2403,7 @@ end_coredump: cleanup: free_note_info(&info); kfree(shdr4extnum); - vfree(vma_filesz); + kvfree(vma_filesz); kfree(phdr4note); kfree(elf); out: |