[FFmpeg-devel] [PATCH 8/8] avcodec/codec_internal: Include codec_tags only when they are needed

Andreas Rheinhardt andreas.rheinhardt at outlook.com
Fri Mar 18 12:52:54 EET 2022


They are only needed for the fuzzer, so check for CONFIG_OSSFUZZ.
This decreases sizeof(FFCodec), which is important given that
FFCodecs reside in .data.rel.ro in case of ELF with
position-independent code which is always loaded and can't be shared
between processes.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
---
 libavcodec/bitpacked_dec.c  |  5 +----
 libavcodec/codec_internal.h | 10 ++++++++++
 libavcodec/hapdec.c         | 13 +++++--------
 tools/target_dec_fuzzer.c   |  2 ++
 4 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/libavcodec/bitpacked_dec.c b/libavcodec/bitpacked_dec.c
index 419550dfe0..b62d88fa8f 100644
--- a/libavcodec/bitpacked_dec.c
+++ b/libavcodec/bitpacked_dec.c
@@ -151,9 +151,6 @@ const FFCodec ff_bitpacked_decoder = {
     .init = bitpacked_init_decoder,
     .decode = bitpacked_decode,
     .p.capabilities = AV_CODEC_CAP_FRAME_THREADS,
-    .codec_tags     = (const uint32_t []){
-        MKTAG('U', 'Y', 'V', 'Y'),
-        FF_CODEC_TAGS_END,
-    },
     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
+    FF_CODEC_TAGS(MKTAG('U', 'Y', 'V', 'Y'))
 };
diff --git a/libavcodec/codec_internal.h b/libavcodec/codec_internal.h
index 596cdbebd2..b6b5b05b44 100644
--- a/libavcodec/codec_internal.h
+++ b/libavcodec/codec_internal.h
@@ -21,6 +21,7 @@
 
 #include <stdint.h>
 
+#include "config.h"
 #include "libavutil/attributes.h"
 #include "codec.h"
 
@@ -74,10 +75,16 @@
  */
 #define FF_CODEC_CAP_SETS_FRAME_PROPS       (1 << 8)
 
+#if CONFIG_OSSFUZZ
 /**
  * FFCodec.codec_tags termination value
  */
 #define FF_CODEC_TAGS_END -1
+#define FF_CODEC_TAGS(...) \
+    .codec_tags = (const uint32_t[]){ __VA_ARGS__, FF_CODEC_TAGS_END },
+#else
+#define FF_CODEC_TAGS(...)
+#endif
 
 typedef struct FFCodecDefault {
     const char *key;
@@ -196,10 +203,13 @@ typedef struct FFCodec {
      */
     const struct AVCodecHWConfigInternal *const *hw_configs;
 
+#if CONFIG_OSSFUZZ
     /**
      * List of supported codec_tags, terminated by FF_CODEC_TAGS_END.
+     * Should be defined with the FF_CODEC_TAGS() macro.
      */
     const uint32_t *codec_tags;
+#endif
 } FFCodec;
 
 static av_always_inline const FFCodec *ffcodec(const AVCodec *codec)
diff --git a/libavcodec/hapdec.c b/libavcodec/hapdec.c
index 4a7ac15a8e..72f922bc5b 100644
--- a/libavcodec/hapdec.c
+++ b/libavcodec/hapdec.c
@@ -486,12 +486,9 @@ const FFCodec ff_hap_decoder = {
                       AV_CODEC_CAP_DR1,
     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE |
                       FF_CODEC_CAP_INIT_CLEANUP,
-    .codec_tags     = (const uint32_t []){
-        MKTAG('H','a','p','1'),
-        MKTAG('H','a','p','5'),
-        MKTAG('H','a','p','Y'),
-        MKTAG('H','a','p','A'),
-        MKTAG('H','a','p','M'),
-        FF_CODEC_TAGS_END,
-    },
+    FF_CODEC_TAGS(MKTAG('H','a','p','1'),
+                  MKTAG('H','a','p','5'),
+                  MKTAG('H','a','p','Y'),
+                  MKTAG('H','a','p','A'),
+                  MKTAG('H','a','p','M'))
 };
diff --git a/tools/target_dec_fuzzer.c b/tools/target_dec_fuzzer.c
index 288aa63313..77f4bb8dd8 100644
--- a/tools/target_dec_fuzzer.c
+++ b/tools/target_dec_fuzzer.c
@@ -279,12 +279,14 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         ctx->sample_rate                        = bytestream2_get_le32(&gbc) & 0x7FFFFFFF;
         ctx->ch_layout.nb_channels              = (unsigned)bytestream2_get_le32(&gbc) % FF_SANE_NB_CHANNELS;
         ctx->block_align                        = bytestream2_get_le32(&gbc) & 0x7FFFFFFF;
+#if CONFIG_OSSFUZZ
         ctx->codec_tag                          = bytestream2_get_le32(&gbc);
         if (c->codec_tags) {
             int n;
             for (n = 0; c->codec_tags[n] != FF_CODEC_TAGS_END; n++);
             ctx->codec_tag = c->codec_tags[ctx->codec_tag % n];
         }
+#endif
         keyframes                               = bytestream2_get_le64(&gbc);
         request_channel_layout                  = bytestream2_get_le64(&gbc);
 
-- 
2.32.0



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