user/libexif: patch CVE-2016-6328 and CVE-2019-9278

1 files changed, 85 insertions, 0 deletions

diff --git a/user/libexif/CVE-2019-9278.patch b/user/libexif/CVE-2019-9278.patch
new file mode 100644
index 000000000..bd15e8d13
--- /dev/null
+++ b/user/libexif/CVE-2019-9278.patch
@@ -0,0 +1,85 @@
+From 75aa73267fdb1e0ebfbc00369e7312bac43d0566 Mon Sep 17 00:00:00 2001
+From: Marcus Meissner <meissner@suse.de>
+Date: Sat, 18 Jan 2020 09:29:42 +0100
+Subject: [PATCH] fix CVE-2019-9278
+
+avoid the use of unsafe integer overflow checking constructs (unsigned integer operations cannot overflow, so "u1 + u2 > u1" can be optimized away)
+
+check for the actual sizes, which should also handle the overflows
+document other places google patched, but do not seem relevant due to other restrictions
+
+fixes https://github.com/libexif/libexif/issues/26
+---
+ libexif/exif-data.c | 28 ++++++++++++++++++----------
+ 1 file changed, 18 insertions(+), 10 deletions(-)
+
+diff --git a/libexif/exif-data.c b/libexif/exif-data.c
+index a6f9c94..6332cd1 100644
+--- a/libexif/exif-data.c
++++ b/libexif/exif-data.c
+@@ -192,9 +192,15 @@ exif_data_load_data_entry (ExifData *data, ExifEntry *entry,
+ 		doff = offset + 8;
+ 
+ 	/* Sanity checks */
+-	if ((doff + s < doff) || (doff + s < s) || (doff + s > size)) {
++	if (doff >= size) {
+ 		exif_log (data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
+-				  "Tag data past end of buffer (%u > %u)", doff+s, size);	
++				  "Tag starts past end of buffer (%u > %u)", doff, size);
++		return 0;
++	}
++
++	if (s > size - doff) {
++		exif_log (data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
++				  "Tag data goes past end of buffer (%u > %u)", doff+s, size);
+ 		return 0;
+ 	}
+ 
+@@ -315,13 +321,14 @@ exif_data_load_data_thumbnail (ExifData *data, const unsigned char *d,
+ 			       unsigned int ds, ExifLong o, ExifLong s)
+ {
+ 	/* Sanity checks */
+-	if ((o + s < o) || (o + s < s) || (o + s > ds) || (o > ds)) {
+-		exif_log (data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
+-			  "Bogus thumbnail offset (%u) or size (%u).",
+-			  o, s);
++	if (o >= ds) {
++		exif_log (data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData", "Bogus thumbnail offset (%u).", o);
++		return;
++	}
++	if (s > ds - o) {
++		exif_log (data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData", "Bogus thumbnail size (%u), max would be %u.", s, ds-o);
+ 		return;
+ 	}
+-
+ 	if (data->data) 
+ 		exif_mem_free (data->priv->mem, data->data);
+ 	if (!(data->data = exif_data_alloc (data, s))) {
+@@ -947,7 +954,7 @@ exif_data_load_data (ExifData *data, const unsigned char *d_orig,
+ 	exif_log (data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData", 
+ 		  "IFD 0 at %i.", (int) offset);
+ 
+-	/* Sanity check the offset, being careful about overflow */
++	/* ds is restricted to 16 bit above, so offset is restricted too, and offset+8 should not overflow. */
+ 	if (offset > ds || offset + 6 + 2 > ds)
+ 		return;
+ 
+@@ -956,6 +963,7 @@ exif_data_load_data (ExifData *data, const unsigned char *d_orig,
+ 
+ 	/* IFD 1 offset */
+ 	n = exif_get_short (d + 6 + offset, data->priv->order);
++	/* offset < 2<<16, n is 16 bit at most, so this op will not overflow */
+ 	if (offset + 6 + 2 + 12 * n + 4 > ds)
+ 		return;
+ 
+@@ -964,8 +972,8 @@ exif_data_load_data (ExifData *data, const unsigned char *d_orig,
+ 		exif_log (data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
+ 			  "IFD 1 at %i.", (int) offset);
+ 
+-		/* Sanity check. */
+-		if (offset > ds || offset + 6 > ds) {
++		/* Sanity check. ds is ensured to be above 6 above, offset is 16bit */
++		if (offset > ds - 6) {
+ 			exif_log (data->priv->log, EXIF_LOG_CODE_CORRUPT_DATA,
+ 				  "ExifData", "Bogus offset of IFD1.");
+ 		} else {