From a0f2d79445366fda3b485e701c84e69d11148259 Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt Date: Wed, 5 Mar 2025 14:19:13 +0100 Subject: [PATCH 2/2] avcodec/exr: Fix potential effective-type violation Storing the values via a union of an uint32_t and a float makes said union the effective type of the destination. This means that it may only be read via such a union which is of course not what our users do/expect. So store the values via AV_WN32A instead which disables effective type analysis (for compilers that perform it). This also fixes a -Wdeclaration-after-statement warning introduced in 0e917389fe73c932049635d947bba076f1709589. Signed-off-by: Andreas Rheinhardt --- libavcodec/exr.c | 29 ++++++++++++----------------- 1 file changed, 12 insertions(+), 17 deletions(-) diff --git a/libavcodec/exr.c b/libavcodec/exr.c index 8b673046c1..1c753edb9f 100644 --- a/libavcodec/exr.c +++ b/libavcodec/exr.c @@ -1383,34 +1383,29 @@ static int decode_block(AVCodecContext *avctx, void *tdata, s->compression == EXR_DWAA || s->compression == EXR_DWAB) { // 32-bit - union av_intfloat32 *ptr_x; + uint8_t *ptr_x = ptr; src = channel_buffer[c]; - ptr_x = (union av_intfloat32 *)ptr; // Zero out the start if xmin is not 0 memset(ptr_x, 0, bxmin); - ptr_x += window_xoffset; + ptr_x += 4 * window_xoffset; - union av_intfloat32 t; if (trc_func && c < 3) { - for (x = 0; x < xsize; x++) { - t.i = bytestream_get_le32(&src); - t.f = trc_func(t.f); - *ptr_x++ = t; + for (int x = 0; x < xsize; x++, ptr_x += 4) { + float f = av_int2float(bytestream_get_le32(&src)); + AV_WN32A(ptr_x, av_float2int(trc_func(f))); } } else if (one_gamma != 1.f) { - for (x = 0; x < xsize; x++) { - t.i = bytestream_get_le32(&src); - if (t.f > 0.0f && c < 3) /* avoid negative values */ - t.f = powf(t.f, one_gamma); - *ptr_x++ = t; + for (int x = 0; x < xsize; x++, ptr_x += 4) { + float f = av_int2float(bytestream_get_le32(&src)); + if (f > 0.0f && c < 3) /* avoid negative values */ + f = powf(f, one_gamma); + AV_WN32A(ptr_x, av_float2int(f)); } } else { - for (x = 0; x < xsize; x++) { - t.i = bytestream_get_le32(&src); - *ptr_x++ = t; - } + for (int x = 0; x < xsize; x++, ptr_x += 4) + AV_WN32A(ptr_x, bytestream_get_le32(&src)); } memset(ptr_x, 0, axmax); } else if (s->pixel_type == EXR_HALF) { -- 2.45.2