| Message ID | 20181026232409.16100-7-linux@rasmusvillemoes.dk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | runtime format string checking | expand |
diff --git a/fs/nfs/nfsroot.c b/fs/nfs/nfsroot.c index effaa4247b91..71db0149eb49 100644 --- a/fs/nfs/nfsroot.c +++ b/fs/nfs/nfsroot.c @@ -261,7 +261,7 @@ static int __init root_nfs_data(char *cmdline) * mess into nfs_root_device. */ len = snprintf(nfs_export_path, sizeof(nfs_export_path), - tmp, utsname()->nodename); + fmtcheck(tmp, "%s", 0), utsname()->nodename); if (len >= (int)sizeof(nfs_export_path)) goto out_devnametoolong; len = snprintf(nfs_root_device, sizeof(nfs_root_device),
tmp is initially the string "/tftpboot/%s", but it may be changed from the calls to root_nfs_parse_options. While an nfsroot= command line option can probably be trusted (or the user gets to keep both pieces), it's also possible for contents to come via a BOOTP option. Do a sanity check of fmt to ensure it doesn't contain odd printf specifiers that would make snprintf go off into the weeds. The lack of the FMTCHECK_NO_EXTRA_ARGS flag (i.e., the last 0 argument) means we allow either no specifiers or precisely one occurrence of %s in tmp. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> --- fs/nfs/nfsroot.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)