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From ebbf0f0133c498d229e94ecf2ed0b41d6e6a142a Mon Sep 17 00:00:00 2001
From: Demi Marie Obenour <athena@invisiblethingslab.com>
Date: Mon, 8 Feb 2021 16:05:01 -0500
Subject: [PATCH] hdrblobInit() needs bounds checks too
Users can pass untrusted data to hdrblobInit() and it must be robust
against this.
Backported from commit 8f4b3c3cab8922a2022b9e47c71f1ecf906077ef
Upstream-Status: Backport [https://github.com/rpm-software-management/rpm/pull/1587/commits/9646711891df851dfbf7ef54cc171574a0914b15]
CVE: CVE-2021-20266
Signed-off-by: Ranjitsinh Rathod <ranjitsinh.rathod@kpit.com>
---
lib/header.c | 48 +++++++++++++++++++++++++++++++-----------------
1 file changed, 31 insertions(+), 17 deletions(-)
diff --git a/lib/header.c b/lib/header.c
index 5b09f8352..ad5b6dc57 100644
--- a/lib/header.c
+++ b/lib/header.c
@@ -11,6 +11,7 @@
#include "system.h"
#include <netdb.h>
#include <errno.h>
+#include <inttypes.h>
#include <rpm/rpmtypes.h>
#include <rpm/rpmstring.h>
#include "lib/header_internal.h"
@@ -1890,6 +1891,25 @@ hdrblob hdrblobFree(hdrblob blob)
return NULL;
}
+static rpmRC hdrblobVerifyLengths(rpmTagVal regionTag, uint32_t il, uint32_t dl,
+ char **emsg) {
+ uint32_t il_max = HEADER_TAGS_MAX;
+ uint32_t dl_max = HEADER_DATA_MAX;
+ if (regionTag == RPMTAG_HEADERSIGNATURES) {
+ il_max = 32;
+ dl_max = 8192;
+ }
+ if (hdrchkRange(il_max, il)) {
+ rasprintf(emsg, _("hdr tags: BAD, no. of tags(%" PRIu32 ") out of range"), il);
+ return RPMRC_FAIL;
+ }
+ if (hdrchkRange(dl_max, dl)) {
+ rasprintf(emsg, _("hdr data: BAD, no. of bytes(%" PRIu32 ") out of range"), dl);
+ return RPMRC_FAIL;
+ }
+ return RPMRC_OK;
+}
+
rpmRC hdrblobRead(FD_t fd, int magic, int exact_size, rpmTagVal regionTag, hdrblob blob, char **emsg)
{
int32_t block[4];
@@ -1902,13 +1922,6 @@ rpmRC hdrblobRead(FD_t fd, int magic, int exact_size, rpmTagVal regionTag, hdrbl
size_t nb;
rpmRC rc = RPMRC_FAIL; /* assume failure */
int xx;
- int32_t il_max = HEADER_TAGS_MAX;
- int32_t dl_max = HEADER_DATA_MAX;
-
- if (regionTag == RPMTAG_HEADERSIGNATURES) {
- il_max = 32;
- dl_max = 8192;
- }
memset(block, 0, sizeof(block));
if ((xx = Freadall(fd, bs, blen)) != blen) {
@@ -1921,15 +1934,9 @@ rpmRC hdrblobRead(FD_t fd, int magic, int exact_size, rpmTagVal regionTag, hdrbl
goto exit;
}
il = ntohl(block[2]);
- if (hdrchkRange(il_max, il)) {
- rasprintf(emsg, _("hdr tags: BAD, no. of tags(%d) out of range"), il);
- goto exit;
- }
dl = ntohl(block[3]);
- if (hdrchkRange(dl_max, dl)) {
- rasprintf(emsg, _("hdr data: BAD, no. of bytes(%d) out of range"), dl);
+ if (hdrblobVerifyLengths(regionTag, il, dl, emsg))
goto exit;
- }
nb = (il * sizeof(struct entryInfo_s)) + dl;
uc = sizeof(il) + sizeof(dl) + nb;
@@ -1973,11 +1980,18 @@ rpmRC hdrblobInit(const void *uh, size_t uc,
struct hdrblob_s *blob, char **emsg)
{
rpmRC rc = RPMRC_FAIL;
-
memset(blob, 0, sizeof(*blob));
+ if (uc && uc < 8) {
+ rasprintf(emsg, _("hdr length: BAD"));
+ goto exit;
+ }
+
blob->ei = (int32_t *) uh; /* discards const */
- blob->il = ntohl(blob->ei[0]);
- blob->dl = ntohl(blob->ei[1]);
+ blob->il = ntohl((uint32_t)(blob->ei[0]));
+ blob->dl = ntohl((uint32_t)(blob->ei[1]));
+ if (hdrblobVerifyLengths(regionTag, blob->il, blob->dl, emsg) != RPMRC_OK)
+ goto exit;
+
blob->pe = (entryInfo) &(blob->ei[2]);
blob->pvlen = sizeof(blob->il) + sizeof(blob->dl) +
(blob->il * sizeof(*blob->pe)) + blob->dl;
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