Backported for 6.0.9


From c992857618db99776917f10bf4f2345a5fdc78b0 Mon Sep 17 00:00:00 2001
From: Yossi Gottlieb <yossigo@gmail.com>
Date: Mon, 22 Feb 2021 15:41:32 +0200
Subject: [PATCH] Fix integer overflow (CVE-2021-21309). (#8522)

On 32-bit systems, setting the proto-max-bulk-len config parameter to a high value may result with integer overflow and a subsequent heap overflow when parsing an input bulk (CVE-2021-21309).

This fix has two parts:

Set a reasonable limit to the config parameter.
Add additional checks to prevent the problem in other potential but unknown code paths.

(cherry picked from commit d32f2e9999ce003bad0bd2c3bca29f64dcce4433)
---
 src/config.c  |  2 +-
 src/sds.c     |  3 +++
 src/zmalloc.c | 10 ++++++++++
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/sds.c b/src/sds.c
index dc664ca9bc4f..4dbb41d2b703 100644
--- a/src/sds.c
+++ b/src/sds.c
@@ -96,6 +96,7 @@ sds sdsnewlen(const void *init, size_t initlen) {
     int hdrlen = sdsHdrSize(type);
     unsigned char *fp; /* flags pointer. */
 
+    assert(initlen + hdrlen + 1 > initlen); /* Catch size_t overflow */
     sh = s_malloc(hdrlen+initlen+1);
     if (sh == NULL) return NULL;
     if (init==SDS_NOINIT)
@@ -214,6 +215,7 @@ sds sdsMakeRoomFor(sds s, size_t addlen) {
     len = sdslen(s);
     sh = (char*)s-sdsHdrSize(oldtype);
     newlen = (len+addlen);
+    assert(newlen > len);   /* Catch size_t overflow */
     if (newlen < SDS_MAX_PREALLOC)
         newlen *= 2;
     else
@@ -227,6 +229,7 @@ sds sdsMakeRoomFor(sds s, size_t addlen) {
     if (type == SDS_TYPE_5) type = SDS_TYPE_8;
 
     hdrlen = sdsHdrSize(type);
+    assert(hdrlen + newlen + 1 > len);  /* Catch size_t overflow */
     if (oldtype==type) {
         newsh = s_realloc(sh, hdrlen+newlen+1);
         if (newsh == NULL) return NULL;

From c6ad876774f3cc11e32681ea02a2eead00f2c521 Mon Sep 17 00:00:00 2001
From: YiyuanGUO <yguoaz@gmail.com>
Date: Wed, 29 Sep 2021 10:20:35 +0300
Subject: [PATCH] Fix integer overflow in _sdsMakeRoomFor (CVE-2021-41099)

---
 src/sds.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/sds.c b/src/sds.c
index 4dbb41d2b703..a43a1a5cbeed 100644
--- a/src/sds.c
+++ b/src/sds.c
@@ -205,7 +205,7 @@ void sdsclear(sds s) {
 sds sdsMakeRoomFor(sds s, size_t addlen) {
     void *sh, *newsh;
     size_t avail = sdsavail(s);
-    size_t len, newlen;
+    size_t len, newlen, reqlen;
     char type, oldtype = s[-1] & SDS_TYPE_MASK;
     int hdrlen;
 
@@ -214,7 +214,7 @@ sds sdsMakeRoomFor(sds s, size_t addlen) {
 
     len = sdslen(s);
     sh = (char*)s-sdsHdrSize(oldtype);
-    newlen = (len+addlen);
+    reqlen = newlen = (len+addlen);
     assert(newlen > len);   /* Catch size_t overflow */
     if (newlen < SDS_MAX_PREALLOC)
         newlen *= 2;
@@ -229,7 +229,7 @@ sds sdsMakeRoomFor(sds s, size_t addlen) {
     if (type == SDS_TYPE_5) type = SDS_TYPE_8;
 
     hdrlen = sdsHdrSize(type);
-    assert(hdrlen + newlen + 1 > len);  /* Catch size_t overflow */
+    assert(hdrlen + newlen + 1 > reqlen);  /* Catch size_t overflow */
     if (oldtype==type) {
         newsh = s_realloc(sh, hdrlen+newlen+1);
         if (newsh == NULL) return NULL;