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authorglebius <glebius@FreeBSD.org>2013-10-29 09:23:51 +0000
committerglebius <glebius@FreeBSD.org>2013-10-29 09:23:51 +0000
commit5d5c0c1a436011bfc73143cec052162af5ca5bda (patch)
tree9e4061c0dcc78d74ae3b7e40f6b75d4567faa6dd /lib/libc/gen
parent492a1ca90c74783f3e8e17f6bec7a153b1dc7efe (diff)
downloadFreeBSD-src-5d5c0c1a436011bfc73143cec052162af5ca5bda.zip
FreeBSD-src-5d5c0c1a436011bfc73143cec052162af5ca5bda.tar.gz
Merge r256537 from head:
Make getutxent(3) more robust against bad utx.log files. Whenever we read zeroes, don't stop processing the file, but read until its end or valid data. In collaboration with: ed Approved by: re (kib)
Diffstat (limited to 'lib/libc/gen')
-rw-r--r--lib/libc/gen/getutxent.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/lib/libc/gen/getutxent.c b/lib/libc/gen/getutxent.c
index 20e8859..1679aa4 100644
--- a/lib/libc/gen/getutxent.c
+++ b/lib/libc/gen/getutxent.c
@@ -122,9 +122,20 @@ getfutxent(struct futx *fu)
if (udb == UTXDB_LOG) {
uint16_t len;
+retry:
if (fread(&len, sizeof(len), 1, uf) != 1)
return (-1);
len = be16toh(len);
+ if (len == 0) {
+ /*
+ * XXX: Though zero-size records are valid in theory,
+ * they can never occur in practice. Zero-size records
+ * indicate file corruption. Seek one byte forward, to
+ * see if we can find a record there.
+ */
+ ungetc('\0', uf);
+ goto retry;
+ }
if (len > sizeof *fu) {
/* Forward compatibility. */
if (fread(fu, sizeof(*fu), 1, uf) != 1)
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