diff options
author | jilles <jilles@FreeBSD.org> | 2010-08-10 22:45:59 +0000 |
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committer | jilles <jilles@FreeBSD.org> | 2010-08-10 22:45:59 +0000 |
commit | 8824c5ab7690895c9f4c64dc73d5cbd0dd4d62e4 (patch) | |
tree | 7e2b11fc91b3dd1fd5d1dc48d4e2e40ebee05f55 /bin | |
parent | 243488333fe36a4095d1e102254a664ed1effc85 (diff) | |
download | FreeBSD-src-8824c5ab7690895c9f4c64dc73d5cbd0dd4d62e4.zip FreeBSD-src-8824c5ab7690895c9f4c64dc73d5cbd0dd4d62e4.tar.gz |
sh: Fix heap-based buffer overflow in pathname generation.
The buffer for generated pathnames could be too small in some cases. It
happened to be always at least PATH_MAX long, so there was never an overflow
if the resulting pathnames would be usable.
This bug may be abused if a script subjects input from an untrusted source
to pathname generation, which a bad idea anyhow. Most shell scripts do not
work on untrusted data. secteam@ says no advisory is necessary.
PR: bin/148733
Reported by: Changming Sun snnn119 at gmail com
MFC after: 10 days
Diffstat (limited to 'bin')
-rw-r--r-- | bin/sh/expand.c | 31 |
1 files changed, 15 insertions, 16 deletions
diff --git a/bin/sh/expand.c b/bin/sh/expand.c index 6c81224..fded6da 100644 --- a/bin/sh/expand.c +++ b/bin/sh/expand.c @@ -1082,8 +1082,8 @@ ifsbreakup(char *string, struct arglist *arglist) * should be escapes. The results are stored in the list exparg. */ -STATIC char *expdir; - +STATIC char expdir[PATH_MAX]; +#define expdir_end (expdir + sizeof(expdir)) STATIC void expandmeta(struct strlist *str, int flag __unused) @@ -1106,14 +1106,7 @@ expandmeta(struct strlist *str, int flag __unused) } savelastp = exparg.lastp; INTOFF; - if (expdir == NULL) { - int i = strlen(str->text); - expdir = ckmalloc(i < 2048 ? 2048 : i); /* XXX */ - } - expmeta(expdir, str->text); - ckfree(expdir); - expdir = NULL; INTON; if (exparg.lastp == savelastp) { /* @@ -1202,6 +1195,8 @@ expmeta(char *enddir, char *name) *enddir++ = *p; if (*p == '\0') break; + if (enddir == expdir_end) + return; } if (metaflag == 0 || lstat(expdir, &statb) >= 0) addfname(expdir); @@ -1216,6 +1211,8 @@ expmeta(char *enddir, char *name) if (*p == CTLESC) p++; *enddir++ = *p++; + if (enddir == expdir_end) + return; } } if (enddir == expdir) { @@ -1249,15 +1246,17 @@ expmeta(char *enddir, char *name) if (dp->d_name[0] == '.' && ! matchdot) continue; if (patmatch(start, dp->d_name, 0)) { - if (atend) { - scopy(dp->d_name, enddir); + if (enddir + dp->d_namlen + 1 > expdir_end) + continue; + memcpy(enddir, dp->d_name, dp->d_namlen + 1); + if (atend) addfname(expdir); - } else { - for (p = enddir, q = dp->d_name; - (*p++ = *q++) != '\0';) + else { + if (enddir + dp->d_namlen + 2 > expdir_end) continue; - p[-1] = '/'; - expmeta(p, endname); + enddir[dp->d_namlen] = '/'; + enddir[dp->d_namlen + 1] = '\0'; + expmeta(enddir + dp->d_namlen + 1, endname); } } } |