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authorLinus Torvalds <torvalds@linux-foundation.org>2019-02-14 15:02:18 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-02-15 09:07:33 +0100
commit4a1802e3676635150f636427e2b917705f98ba64 (patch)
tree72e8b165a290feeeaab205b25101954158e5e2fe
parentb7ec3f91215a87cbb2fdbbf58e301a5db9cbbc9f (diff)
Revert "exec: load_script: don't blindly truncate shebang string"
commit cb5b020a8d38f77209d0472a0fea755299a8ec78 upstream. This reverts commit 8099b047ecc431518b9bb6bdbba3549bbecdc343. It turns out that people do actually depend on the shebang string being truncated, and on the fact that an interpreter (like perl) will often just re-interpret it entirely to get the full argument list. Reported-by: Samuel Dionne-Riel <samuel@dionne-riel.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/binfmt_script.c10
1 files changed, 3 insertions, 7 deletions
diff --git a/fs/binfmt_script.c b/fs/binfmt_script.c
index 634bdbb23851..afdf4e3cafc2 100644
--- a/fs/binfmt_script.c
+++ b/fs/binfmt_script.c
@@ -43,14 +43,10 @@ static int load_script(struct linux_binprm *bprm)
fput(bprm->file);
bprm->file = NULL;
- for (cp = bprm->buf+2;; cp++) {
- if (cp >= bprm->buf + BINPRM_BUF_SIZE)
- return -ENOEXEC;
- if (!*cp || (*cp == '\n'))
- break;
- }
+ bprm->buf[BINPRM_BUF_SIZE - 1] = '\0';
+ if ((cp = strchr(bprm->buf, '\n')) == NULL)
+ cp = bprm->buf+BINPRM_BUF_SIZE-1;
*cp = '\0';
-
while (cp > bprm->buf) {
cp--;
if ((*cp == ' ') || (*cp == '\t'))