michal-grzedzicki / rpms / rpm

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Adjusted lib/package.c section to apply, and 4.11.x requires the
same change in lib/signature.c as well.

From 89dce2b91d7d73a1e225461a7392c3d6d7a30a95 Mon Sep 17 00:00:00 2001
From: Panu Matilainen <pmatilai@redhat.com>
Date: Wed, 19 Oct 2016 14:48:08 +0300
Subject: [PATCH] Verify data is within range and does not overlap in
 headerVerifyInfo()

Checking whether data start offset is within header data area is of no use
whatsoever if the entire chunk doesn't fit. Validate the entire data
fits within range and that it does not overlap, however with string
types we can only check the array size is sane but we cant check the
actual content.

Adjust the upper limit for region trailer in headerVerifyRegion() so
it fits the new rules, but in reality calling headerVerifyInfo() for
the region tags is rather pointless since they're so different.

Partial fix for RhBug:1373107.
---
 lib/header.c  | 21 ++++++++++++++++-----
 lib/package.c |  2 +-
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/lib/header.c b/lib/header.c
index 7f7c115..cac5c94 100644
--- a/lib/header.c
+++ b/lib/header.c
@@ -196,7 +196,8 @@ int headerVerifyInfo(int il, int dl, const void * pev, void * iv, int negate)
 {
     entryInfo pe = (entryInfo) pev;
     entryInfo info = iv;
-    int i;
+    int i, tsize;
+    int32_t end = 0;
 
     for (i = 0; i < il; i++) {
 	info->tag = ntohl(pe[i].tag);
@@ -206,16 +207,26 @@ int headerVerifyInfo(int il, int dl, const void * pev, void * iv, int negate)
 	    info->offset = -info->offset;
 	info->count = ntohl(pe[i].count);
 
+	/* Previous data must not overlap */
+	if (end > info->offset)
+	    return i;
+
 	if (hdrchkType(info->type))
 	    return i;
 	if (hdrchkAlign(info->type, info->offset))
 	    return i;
-	if (hdrchkRange(dl, info->offset))
-	    return i;
-	if (hdrchkData(info->count))
-	    return i;
 
+	/* For string types we can only check the array size is sane */
+	tsize = typeSizes[info->type];
+	if (tsize < 1)
+	    tsize = 1;
+
+	/* Verify the data actually fits */
+	end = info->offset + (info->count * tsize);
+	if (hdrchkRange(dl, end))
+	    return i;
     }
+
     return -1;
 }

diff --git a/lib/package.c b/lib/package.c
index b6bea09..bb83163 100644
--- a/lib/package.c
+++ b/lib/package.c
@@ -339,7 +339,7 @@ static rpmRC headerVerify(rpmKeyring keyring, rpmVSFlags vsflags,
     (void) memcpy(&info, regionEnd, REGION_TAG_COUNT);
     regionEnd += REGION_TAG_COUNT;
 
-    if (headerVerifyInfo(1, il * sizeof(*pe), &info, &entry.info, 1) != -1 ||
+    if (headerVerifyInfo(1, il * sizeof(*pe) + REGION_TAG_COUNT, &info, &entry.info, 1) != -1 ||
 	!(entry.info.tag == RPMTAG_HEADERIMMUTABLE
        && entry.info.type == REGION_TAG_TYPE
        && entry.info.count == REGION_TAG_COUNT))
diff --git a/lib/signature.c b/lib/signature.c
index d8017dc..ddf2eb8 100644
--- a/lib/signature.c
+++ b/lib/signature.c
@@ -165,7 +165,7 @@ rpmRC rpmReadSignature(FD_t fd, Header * sighp, sigType sig_type, char ** msg)
 	}
 	dataEnd += REGION_TAG_COUNT;
 
-	xx = headerVerifyInfo(1, il * sizeof(*pe), &info, &entry.info, 1);
+	xx = headerVerifyInfo(1, il * sizeof(*pe) + REGION_TAG_COUNT, &info, &entry.info, 1);
 	if (xx != -1 ||
 	    !((entry.info.tag == RPMTAG_HEADERSIGNATURES || entry.info.tag == RPMTAG_HEADERIMAGE)
 	   && entry.info.type == REGION_TAG_TYPE