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| author | Colin Watson | 2010-04-26 14:21:27 +0200 |
|---|---|---|
| committer | Denys Vlasenko | 2010-04-26 14:21:27 +0200 |
| commit | 3963d943f8a9b4ef89f000b5e1424e63dba920f5 (patch) | |
| tree | addf83c843ab6b0651c08bee282379541bc8fd9b /shell/ash.c | |
| parent | 920185c69ac9addf06cb47a0f2336e075d6dacb2 (diff) | |
| download | busybox-3963d943f8a9b4ef89f000b5e1424e63dba920f5.zip busybox-3963d943f8a9b4ef89f000b5e1424e63dba920f5.tar.gz | |
ash: refresh stack pointers after makestrspace in rmescapes
Without this, rmescapes sometimes returns random garbage while
performing parameter expansions such as ${foo#bar}, in the event that
the allocation of r happens to need to reallocate the stack and hence
invalidate str and p. I'd love to provide a test case but unfortunately
it's dependent on exact stack layout, so I don't have anything simpler
than the situation described in
https://bugs.launchpad.net/ubuntu/+source/partman-base/+bug/527401/comments/23
which involved a sequence of foo="${foo#*, }" expansions on a long
string inside our RAID configuration tool.
The same fix has been in dash since 2007-09-26, contributed by Roy
Marples <uberlord@gentoo.org>. I actually came up with it independently
almost to the character, but then synced it up with the variable naming
used in dash when I noticed that change afterwards.
Signed-off-by: Colin Watson <cjwatson@ubuntu.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'shell/ash.c')
| -rw-r--r-- | shell/ash.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/shell/ash.c b/shell/ash.c index 9d55f89..ec5e0b8 100644 --- a/shell/ash.c +++ b/shell/ash.c @@ -5425,7 +5425,11 @@ rmescapes(char *str, int flag) size_t fulllen = len + strlen(p) + 1; if (flag & RMESCAPE_GROW) { + int strloc = str - (char *)stackblock(); r = makestrspace(fulllen, expdest); + /* p and str may be invalidated by makestrspace */ + str = (char *)stackblock() + strloc; + p = str + len; } else if (flag & RMESCAPE_HEAP) { r = ckmalloc(fulllen); } else { |