[FFmpeg-devel] [PATCH 1/6] avcodec/tiff: Fix handling of av_strdup() failures
Stefano Sabatini
stefasab at gmail.com
Sun Mar 10 17:25:18 EET 2024
On date Sunday 2024-03-10 15:12:16 +0100, Andreas Rheinhardt wrote:
> For unknown geokey values, get_geokey_val() returns
> "Unknown-%d" with val being used for %d. This string
> is allocated and therefore all the known geokey values
> (static strings) are strdup'ed. In case this fails
> it is either ignored or treated as "Unknown-%d".
> (Furthermore it is possible to call av_strdup(NULL),
> although this is not documented to be legal.)
>
> This commit changes this by only returning the static strings
> in get_geokey_val(); the unknown handling and strdup'ing
> is moved out of it.
>
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
> ---
> libavcodec/tiff.c | 35 ++++++++++++++++-------------------
> 1 file changed, 16 insertions(+), 19 deletions(-)
>
> diff --git a/libavcodec/tiff.c b/libavcodec/tiff.c
> index cb4d378753..4c7460cf41 100644
> --- a/libavcodec/tiff.c
> +++ b/libavcodec/tiff.c
> @@ -36,6 +36,7 @@
> #include <float.h>
>
> #include "libavutil/attributes.h"
> +#include "libavutil/avstring.h"
> #include "libavutil/error.h"
> #include "libavutil/intreadwrite.h"
> #include "libavutil/opt.h"
> @@ -179,19 +180,17 @@ static const char *search_keyval(const TiffGeoTagKeyName *keys, int n, int id)
> return NULL;
> }
>
> -static char *get_geokey_val(int key, int val)
> +static const char *get_geokey_val(int key, uint16_t val)
> {
> - char *ap;
> -
> if (val == TIFF_GEO_KEY_UNDEFINED)
> - return av_strdup("undefined");
> + return "undefined";
> if (val == TIFF_GEO_KEY_USER_DEFINED)
> - return av_strdup("User-Defined");
> + return "User-Defined";
>
> #define RET_GEOKEY_VAL(TYPE, array)\
> if (val >= TIFF_##TYPE##_OFFSET &&\
> val - TIFF_##TYPE##_OFFSET < FF_ARRAY_ELEMS(tiff_##array##_codes))\
> - return av_strdup(tiff_##array##_codes[val - TIFF_##TYPE##_OFFSET]);
> + return tiff_##array##_codes[val - TIFF_##TYPE##_OFFSET];
>
> switch (key) {
> case TIFF_GT_MODEL_TYPE_GEOKEY:
> @@ -224,13 +223,9 @@ static char *get_geokey_val(int key, int val)
> RET_GEOKEY_VAL(PRIME_MERIDIAN, prime_meridian);
> break;
> case TIFF_PROJECTED_CS_TYPE_GEOKEY:
> - ap = av_strdup(search_keyval(tiff_proj_cs_type_codes, FF_ARRAY_ELEMS(tiff_proj_cs_type_codes), val));
> - if(ap) return ap;
> - break;
> + return search_keyval(tiff_proj_cs_type_codes, FF_ARRAY_ELEMS(tiff_proj_cs_type_codes), val);
> case TIFF_PROJECTION_GEOKEY:
> - ap = av_strdup(search_keyval(tiff_projection_codes, FF_ARRAY_ELEMS(tiff_projection_codes), val));
> - if(ap) return ap;
> - break;
> + return search_keyval(tiff_projection_codes, FF_ARRAY_ELEMS(tiff_projection_codes), val);
> case TIFF_PROJ_COORD_TRANS_GEOKEY:
> RET_GEOKEY_VAL(COORD_TRANS, coord_trans);
> break;
> @@ -241,10 +236,7 @@ static char *get_geokey_val(int key, int val)
>
> }
>
> - ap = av_malloc(14);
> - if (ap)
> - snprintf(ap, 14, "Unknown-%d", val);
> - return ap;
> + return NULL;
> }
>
> static char *doubles2str(double *dp, int count, const char *sep)
> @@ -1634,9 +1626,14 @@ static int tiff_decode_tag(TiffContext *s, AVFrame *frame)
> s->geotags[i].type = ff_tget_short(&s->gb, s->le);
> s->geotags[i].count = ff_tget_short(&s->gb, s->le);
>
> - if (!s->geotags[i].type)
> - s->geotags[i].val = get_geokey_val(s->geotags[i].key, ff_tget_short(&s->gb, s->le));
> - else
> + if (!s->geotags[i].type) {
> + uint16_t val = ff_tget_short(&s->gb, s->le);
> + const char *str = get_geokey_val(s->geotags[i].key, val);
> +
> + s->geotags[i].val = str ? av_strdup(str) : av_asprintf("Unknown-%u", val);
> + if (!s->geotags[i].val)
> + return AVERROR(ENOMEM);
> + } else
> s->geotags[i].offset = ff_tget_short(&s->gb, s->le);
nit++: you migth factorize the ff_tget_short call
> }
> break;
LGTM.
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