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authorLinus Torvalds <torvalds@linux-foundation.org>2009-02-06 18:10:04 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-02-06 18:10:04 -0800
commit1d87b0d388c65feb890f1e0aa832338a33d0760f (patch)
treeca1980ce84f2fb1bc7952738e32f9657dc4d0154
parentd4cf109f05ff04c6f5065c3e14165ef01a57dd53 (diff)
parent92dc07b1f988e8c237a38e23be660b9b8533e6fd (diff)
Merge branch 'to-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/frob/linux-2.6-roland
* 'to-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/frob/linux-2.6-roland: elf core dump: fix get_user use
-rw-r--r--fs/binfmt_elf.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index e3ff2b9e602f..33b7235f853b 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1208,9 +1208,11 @@ static unsigned long vma_dump_size(struct vm_area_struct *vma,
* check for an ELF header. If we find one, dump the first page to
* aid in determining what was mapped here.
*/
- if (FILTER(ELF_HEADERS) && vma->vm_file != NULL && vma->vm_pgoff == 0) {
+ if (FILTER(ELF_HEADERS) &&
+ vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) {
u32 __user *header = (u32 __user *) vma->vm_start;
u32 word;
+ mm_segment_t fs = get_fs();
/*
* Doing it this way gets the constant folded by GCC.
*/
@@ -1223,7 +1225,15 @@ static unsigned long vma_dump_size(struct vm_area_struct *vma,
magic.elfmag[EI_MAG1] = ELFMAG1;
magic.elfmag[EI_MAG2] = ELFMAG2;
magic.elfmag[EI_MAG3] = ELFMAG3;
- if (get_user(word, header) == 0 && word == magic.cmp)
+ /*
+ * Switch to the user "segment" for get_user(),
+ * then put back what elf_core_dump() had in place.
+ */
+ set_fs(USER_DS);
+ if (unlikely(get_user(word, header)))
+ word = 0;
+ set_fs(fs);
+ if (word == magic.cmp)
return PAGE_SIZE;
}

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