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authorJim Meyering <jim@meyering.net>2010-02-08 19:28:38 +0100
committerAnthony Liguori <aliguori@us.ibm.com>2010-02-10 14:00:53 -0600
commit6265eb26a375179f193f792e4f0d49036d2cf052 (patch)
tree42daed0971626ac0a038fa9d695c9002a52dfae0 /slirp/misc.c
parent47116d1c90cdac94cb9da270320dcf0d5ce1cfe2 (diff)
downloadqemu-arm-6265eb26a375179f193f792e4f0d49036d2cf052.tar.gz
don't dereference NULL after failed strdup
Most of these are obvious NULL-deref bug fixes, for example, the ones in these files: block/curl.c net.c slirp/misc.c and the first one in block/vvfat.c. The others in block/vvfat.c may not lead to an immediate segfault, but I traced the two schedule_rename(..., strdup(path)) uses, and a failed strdup would appear to trigger this assertion in handle_renames_and_mkdirs: assert(commit->path); The conversion to use qemu_strdup in envlist_to_environ is not technically needed, but does avoid a theoretical leak in the caller when strdup fails for one value, but later succeeds in allocating another buffer(plausible, if one string length is much larger than the others). The caller does not know the length of the returned list, and as such can only free pointers until it hits the first NULL. If there are non-NULL pointers beyond the first, their buffers would be leaked. This one is admittedly far-fetched. The two in linux-user/main.c are worth fixing to ensure that an OOM error is diagnosed up front, rather than letting it provoke some harder-to-diagnose secondary error, in case of exec failure, or worse, in case the exec succeeds but with an invalid list of command line options. However, considering how unlikely it is to encounter a failed strdup early in main, this isn't a big deal. Note that adding the required uses of qemu_strdup here and in envlist.c induce link failures because qemu_strdup is not currently in any library they're linked with. So for now, I've omitted those changes, as well as the fixes in target-i386/helper.c and target-sparc/helper.c. If you'd like to see the above discussion (or anything else) in the commit log, just let me know and I'll be happy to adjust. >From 9af42864fd1ea666bd25e2cecfdfae74c20aa8c7 Mon Sep 17 00:00:00 2001 From: Jim Meyering <meyering@redhat.com> Date: Mon, 8 Feb 2010 18:29:29 +0100 Subject: [PATCH] don't dereference NULL after failed strdup Handle failing strdup by replacing each use with qemu_strdup, so as not to dereference NULL or trigger a failing assertion. * block/curl.c (curl_open): s/\bstrdup\b/qemu_strdup/ * block/vvfat.c (init_directories): Likewise. (get_cluster_count_for_direntry, check_directory_consistency): Likewise. * net.c (parse_host_src_port): Likewise. * slirp/misc.c (fork_exec): Likewise. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Diffstat (limited to 'slirp/misc.c')
-rw-r--r--slirp/misc.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/slirp/misc.c b/slirp/misc.c
index 05f4fb329f..dcb1dc117b 100644
--- a/slirp/misc.c
+++ b/slirp/misc.c
@@ -179,7 +179,7 @@ fork_exec(struct socket *so, const char *ex, int do_pty)
close(s);
i = 0;
- bptr = strdup(ex); /* No need to free() this */
+ bptr = qemu_strdup(ex); /* No need to free() this */
if (do_pty == 1) {
/* Setup "slirp.telnetd -x" */
argv[i++] = "slirp.telnetd";