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authorAlexey Dobriyan <adobriyan@gmail.com>2018-06-15 01:27:24 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-15 01:55:24 +0300
commit86a2bb5ad83161cc687671bdf188699e137ae226 (patch)
tree8556deca018ee7b44028d03bef993118b945d188
parentc2574aaa5d98684519f0dfa64abe6896aeb124c6 (diff)
downloadlinux-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.c17
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: