From 6e3c30637d46e0684447084f152a849f8e7acc6b Mon Sep 17 00:00:00 2001 From: Alan Somers Date: Wed, 24 May 2017 16:30:38 +0000 Subject: [PATCH] Fix a buffer overflow in bootparamd(8) If /etc/bootparams contains a line with an excessively long pathname, and a client asks for that path, then bootparamd will overflow a buffer and crash while parsing that line. This is not remotely exploitable since it requires a malformed /etc/bootparams file. Reported by: Coverity CID: 1305954 MFC after: 1 week Sponsored by: Spectra Logic Corp --- usr.sbin/bootparamd/bootparamd/bootparamd.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/usr.sbin/bootparamd/bootparamd/bootparamd.c b/usr.sbin/bootparamd/bootparamd/bootparamd.c index 09213058bbd4..baccd42d427b 100644 --- a/usr.sbin/bootparamd/bootparamd/bootparamd.c +++ b/usr.sbin/bootparamd/bootparamd/bootparamd.c @@ -199,7 +199,10 @@ int blen; int ch, pch, fid_len, res = 0; int match = 0; - char info[MAX_FILEID + MAX_PATH_LEN+MAX_MACHINE_NAME + 3]; +#define INFOLEN 1343 + _Static_assert(INFOLEN >= MAX_FILEID + MAX_PATH_LEN+MAX_MACHINE_NAME + 3, + "INFOLEN isn't large enough"); + char info[INFOLEN + 1]; bpf = fopen(bootpfile, "r"); if ( ! bpf ) @@ -251,8 +254,9 @@ int blen; info of the file */ if (match) { - fid_len = strlen(fileid); - while ( ! res && (fscanf(bpf,"%s", info)) > 0) { /* read a string */ +#define AS_FORMAT(d) "%" #d "s" +#define REXPAND(d) AS_FORMAT(d) /* Force another preprocessor expansion */ + while ( ! res && (fscanf(bpf, REXPAND(INFOLEN), info)) > 0) { ch = getc(bpf); /* and a character */ if ( *info != '#' ) { /* Comment ? */ if (! strncmp(info, fileid, fid_len) && *(info + fid_len) == '=') {