diff options
| author | Florian Weimer <fweimer@redhat.com> | 2015-10-02 11:34:13 +0200 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2015-10-02 11:34:13 +0200 |
| commit | 676599b36a92f3c201c5682ee7a5caddd9f370a4 (patch) | |
| tree | 6860752c26ccab76ee9db5e60ff465d1edf25feb /grp/putgrent.c | |
| parent | b0f81637d5bda47be93bac34b68f429a12979321 (diff) | |
Harden putpwent, putgrent, putspent, putspent against injection [BZ #18724]
This prevents injection of ':' and '\n' into output functions which
use the NSS files database syntax. Critical fields (user/group names
and file system paths) are checked strictly. For backwards
compatibility, the GECOS field is rewritten instead.
The getent program is adjusted to use the put*ent functions in libc,
instead of local copies. This changes the behavior of getent if user
names start with '-' or '+'.
Diffstat (limited to 'grp/putgrent.c')
| -rw-r--r-- | grp/putgrent.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/grp/putgrent.c b/grp/putgrent.c index e4d662c6b5..1ac7f19a0b 100644 --- a/grp/putgrent.c +++ b/grp/putgrent.c @@ -16,7 +16,9 @@ <http://www.gnu.org/licenses/>. */ #include <errno.h> +#include <nss.h> #include <stdio.h> +#include <string.h> #include <grp.h> #define flockfile(s) _IO_flockfile (s) @@ -27,13 +29,14 @@ /* Write an entry to the given stream. This must know the format of the group file. */ int -putgrent (gr, stream) - const struct group *gr; - FILE *stream; +putgrent (const struct group *gr, FILE *stream) { int retval; - if (__glibc_unlikely (gr == NULL) || __glibc_unlikely (stream == NULL)) + if (__glibc_unlikely (gr == NULL) || __glibc_unlikely (stream == NULL) + || gr->gr_name == NULL || !__nss_valid_field (gr->gr_name) + || !__nss_valid_field (gr->gr_passwd) + || !__nss_valid_list_field (gr->gr_mem)) { __set_errno (EINVAL); return -1; @@ -56,9 +59,7 @@ putgrent (gr, stream) if (gr->gr_mem != NULL) { - int i; - - for (i = 0 ; gr->gr_mem[i] != NULL; i++) + for (size_t i = 0; gr->gr_mem[i] != NULL; i++) if (fprintf (stream, i == 0 ? "%s" : ",%s", gr->gr_mem[i]) < 0) { /* What else can we do? */ |