media-libs/libwebp: backport fix for CVE-2023-1999

Bug: https://bugs.gentoo.org/909369
Signed-off-by: Stephan Hartmann <sultan@gentoo.org>

1 files changed, 50 insertions, 0 deletions

diff --git a/media-libs/libwebp/files/libwebp-1.2.4-CVE-2023-1999.patch b/media-libs/libwebp/files/libwebp-1.2.4-CVE-2023-1999.patch
new file mode 100644
index 000000000000..9c023712a5aa
--- /dev/null
+++ b/media-libs/libwebp/files/libwebp-1.2.4-CVE-2023-1999.patch
@@ -0,0 +1,50 @@
+commit a486d800b60d0af4cc0836bf7ed8f21e12974129
+Author: James Zern <jzern@google.com>
+Date:   Wed Feb 22 22:15:47 2023 -0800
+
+    EncodeAlphaInternal: clear result->bw on error
+    
+    This avoids a double free should the function fail prior to
+    VP8BitWriterInit() and a previous trial result's buffer carried over.
+    Previously in ApplyFiltersAndEncode() trial.bw (with a previous
+    iteration's buffer) would be freed, followed by best.bw pointing to the
+    same buffer.
+    
+    Since:
+    187d379d add a fallback to ALPHA_NO_COMPRESSION
+    
+    In addition, check the return value of VP8BitWriterInit() in this
+    function.
+    
+    Bug: webp:603
+    Change-Id: Ic258381ee26c8c16bc211d157c8153831c8c6910
+
+diff --git a/src/enc/alpha_enc.c b/src/enc/alpha_enc.c
+index f7c02690..7d205586 100644
+--- a/src/enc/alpha_enc.c
++++ b/src/enc/alpha_enc.c
+@@ -13,6 +13,7 @@
+ 
+ #include <assert.h>
+ #include <stdlib.h>
++#include <string.h>
+ 
+ #include "src/enc/vp8i_enc.h"
+ #include "src/dsp/dsp.h"
+@@ -148,6 +149,7 @@ static int EncodeAlphaInternal(const uint8_t* const data, int width, int height,
+       }
+     } else {
+       VP8LBitWriterWipeOut(&tmp_bw);
++      memset(&result->bw, 0, sizeof(result->bw));
+       return 0;
+     }
+   }
+@@ -162,7 +164,7 @@ static int EncodeAlphaInternal(const uint8_t* const data, int width, int height,
+   header = method | (filter << 2);
+   if (reduce_levels) header |= ALPHA_PREPROCESSED_LEVELS << 4;
+ 
+-  VP8BitWriterInit(&result->bw, ALPHA_HEADER_LEN + output_size);
++  if (!VP8BitWriterInit(&result->bw, ALPHA_HEADER_LEN + output_size)) ok = 0;
+   ok = ok && VP8BitWriterAppend(&result->bw, &header, ALPHA_HEADER_LEN);
+   ok = ok && VP8BitWriterAppend(&result->bw, output, output_size);
+