aboutsummaryrefslogtreecommitdiff
path: root/package/libexif/0005-fix-CVE-2019-9278.patch
diff options
context:
space:
mode:
Diffstat (limited to 'package/libexif/0005-fix-CVE-2019-9278.patch')
-rw-r--r--package/libexif/0005-fix-CVE-2019-9278.patch90
1 files changed, 90 insertions, 0 deletions
diff --git a/package/libexif/0005-fix-CVE-2019-9278.patch b/package/libexif/0005-fix-CVE-2019-9278.patch
new file mode 100644
index 0000000000..f708b2ae54
--- /dev/null
+++ b/package/libexif/0005-fix-CVE-2019-9278.patch
@@ -0,0 +1,90 @@
+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
+
+Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
+---
+ 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 {
+--
+2.20.1
+