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From 011d25d5f653246770fa58b7dcff26740369c6ef Mon Sep 17 00:00:00 2001
From: Jeremy Allison <jra@samba.org>
Date: Fri, 15 Jun 2018 15:08:17 -0700
Subject: [PATCH] CVE-2018-10858: libsmb: Harden smbc_readdir_internal()
against returns from malicious servers.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=13453
CVE-2018-10858: Insufficient input validation on client directory
listing in libsmbclient.
Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
---
source3/libsmb/libsmb_dir.c | 57 +++++++++++++++++++++++++++++++-----
source3/libsmb/libsmb_path.c | 2 +-
2 files changed, 51 insertions(+), 8 deletions(-)
diff --git a/source3/libsmb/libsmb_dir.c b/source3/libsmb/libsmb_dir.c
index 72441c46736..54c2bcb3c73 100644
--- a/source3/libsmb/libsmb_dir.c
+++ b/source3/libsmb/libsmb_dir.c
@@ -943,27 +943,47 @@ SMBC_closedir_ctx(SMBCCTX *context,
}
-static void
+static int
smbc_readdir_internal(SMBCCTX * context,
struct smbc_dirent *dest,
struct smbc_dirent *src,
int max_namebuf_len)
{
if (smbc_getOptionUrlEncodeReaddirEntries(context)) {
+ int remaining_len;
/* url-encode the name. get back remaining buffer space */
- max_namebuf_len =
+ remaining_len =
smbc_urlencode(dest->name, src->name, max_namebuf_len);
+ /* -1 means no null termination. */
+ if (remaining_len < 0) {
+ return -1;
+ }
+
/* We now know the name length */
dest->namelen = strlen(dest->name);
+ if (dest->namelen + 1 < 1) {
+ /* Integer wrap. */
+ return -1;
+ }
+
+ if (dest->namelen + 1 >= max_namebuf_len) {
+ /* Out of space for comment. */
+ return -1;
+ }
+
/* Save the pointer to the beginning of the comment */
dest->comment = dest->name + dest->namelen + 1;
+ if (remaining_len < 1) {
+ /* No room for comment null termination. */
+ return -1;
+ }
+
/* Copy the comment */
- strncpy(dest->comment, src->comment, max_namebuf_len - 1);
- dest->comment[max_namebuf_len - 1] = '\0';
+ strlcpy(dest->comment, src->comment, remaining_len);
/* Save other fields */
dest->smbc_type = src->smbc_type;
@@ -973,10 +993,21 @@ smbc_readdir_internal(SMBCCTX * context,
} else {
/* No encoding. Just copy the entry as is. */
+ if (src->dirlen > max_namebuf_len) {
+ return -1;
+ }
memcpy(dest, src, src->dirlen);
+ if (src->namelen + 1 < 1) {
+ /* Integer wrap */
+ return -1;
+ }
+ if (src->namelen + 1 >= max_namebuf_len) {
+ /* Comment off the end. */
+ return -1;
+ }
dest->comment = (char *)(&dest->name + src->namelen + 1);
}
-
+ return 0;
}
/*
@@ -988,6 +1019,7 @@ SMBC_readdir_ctx(SMBCCTX *context,
SMBCFILE *dir)
{
int maxlen;
+ int ret;
struct smbc_dirent *dirp, *dirent;
TALLOC_CTX *frame = talloc_stackframe();
@@ -1037,7 +1069,12 @@ SMBC_readdir_ctx(SMBCCTX *context,
dirp = &context->internal->dirent;
maxlen = sizeof(context->internal->_dirent_name);
- smbc_readdir_internal(context, dirp, dirent, maxlen);
+ ret = smbc_readdir_internal(context, dirp, dirent, maxlen);
+ if (ret == -1) {
+ errno = EINVAL;
+ TALLOC_FREE(frame);
+ return NULL;
+ }
dir->dir_next = dir->dir_next->next;
@@ -1095,6 +1132,7 @@ SMBC_getdents_ctx(SMBCCTX *context,
*/
while ((dirlist = dir->dir_next)) {
+ int ret;
struct smbc_dirent *dirent;
struct smbc_dirent *currentEntry = (struct smbc_dirent *)ndir;
@@ -1109,8 +1147,13 @@ SMBC_getdents_ctx(SMBCCTX *context,
/* Do urlencoding of next entry, if so selected */
dirent = &context->internal->dirent;
maxlen = sizeof(context->internal->_dirent_name);
- smbc_readdir_internal(context, dirent,
+ ret = smbc_readdir_internal(context, dirent,
dirlist->dirent, maxlen);
+ if (ret == -1) {
+ errno = EINVAL;
+ TALLOC_FREE(frame);
+ return -1;
+ }
reqd = dirent->dirlen;
diff --git a/source3/libsmb/libsmb_path.c b/source3/libsmb/libsmb_path.c
index ed70ab37550..5b53b386a67 100644
--- a/source3/libsmb/libsmb_path.c
+++ b/source3/libsmb/libsmb_path.c
@@ -173,7 +173,7 @@ smbc_urlencode(char *dest,
}
}
- if (max_dest_len == 0) {
+ if (max_dest_len <= 0) {
/* Ensure we return -1 if no null termination. */
return -1;
}
--
2.18.0
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