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[FFmpeg-devel,v3,1/4] libavutil/imgutils: add utility to get plane sizes

Message ID 11b6ffd9e674f497508f1b7cbad1dee4284f78c7.1594660141.git.bkkim@google.com
State New
Headers show
Series [FFmpeg-devel,v3,1/4] libavutil/imgutils: add utility to get plane sizes
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Commit Message

Brian Kim July 13, 2020, 5:09 p.m. UTC
This utility helps avoid undefined behavior when doing things like
checking how much memory we need to allocate for an image before we have
allocated a buffer.

Signed-off-by: Brian Kim <bkkim@google.com>
---
 doc/APIchanges       |  3 ++
 libavutil/imgutils.c | 98 +++++++++++++++++++++++++++++++++-----------
 libavutil/imgutils.h | 11 +++++
 libavutil/version.h  |  2 +-
 4 files changed, 90 insertions(+), 24 deletions(-)

Comments

James Almer July 13, 2020, 6:22 p.m. UTC | #1
On 7/13/2020 2:09 PM, Brian Kim wrote:
> This utility helps avoid undefined behavior when doing things like
> checking how much memory we need to allocate for an image before we have
> allocated a buffer.
> 
> Signed-off-by: Brian Kim <bkkim@google.com>
> ---
>  doc/APIchanges       |  3 ++
>  libavutil/imgutils.c | 98 +++++++++++++++++++++++++++++++++-----------
>  libavutil/imgutils.h | 11 +++++
>  libavutil/version.h  |  2 +-
>  4 files changed, 90 insertions(+), 24 deletions(-)
> 
> diff --git a/doc/APIchanges b/doc/APIchanges
> index 1d6cc36b8c..44defd9ca8 100644
> --- a/doc/APIchanges
> +++ b/doc/APIchanges
> @@ -15,6 +15,9 @@ libavutil:     2017-10-21
>  
>  API changes, most recent first:
>  
> +2020-07-xx - xxxxxxxxxx - lavu 56.56.100 - imgutils.h
> +  Add av_image_fill_plane_sizes().
> +
>  2020-06-12 - b09fb030c1 - lavu 56.55.100 - pixdesc.h
>    Add AV_PIX_FMT_X2RGB10.
>  
> diff --git a/libavutil/imgutils.c b/libavutil/imgutils.c
> index 7f9c1b632c..345b7fa94c 100644
> --- a/libavutil/imgutils.c
> +++ b/libavutil/imgutils.c
> @@ -108,45 +108,69 @@ int av_image_fill_linesizes(int linesizes[4], enum AVPixelFormat pix_fmt, int wi
>      return 0;
>  }
>  
> -int av_image_fill_pointers(uint8_t *data[4], enum AVPixelFormat pix_fmt, int height,
> -                           uint8_t *ptr, const int linesizes[4])
> +int av_image_fill_plane_sizes(size_t sizes[4], enum AVPixelFormat pix_fmt,
> +                              int height, const ptrdiff_t linesizes[4])
>  {
> -    int i, total_size, size[4] = { 0 }, has_plane[4] = { 0 };
> +    int i, has_plane[4] = { 0 };
>  
>      const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
> -    memset(data     , 0, sizeof(data[0])*4);
> +    memset(sizes    , 0, sizeof(sizes[0])*4);
>  
>      if (!desc || desc->flags & AV_PIX_FMT_FLAG_HWACCEL)
>          return AVERROR(EINVAL);
>  
> -    data[0] = ptr;
> -    if (linesizes[0] > (INT_MAX - 1024) / height)
> +    if (linesizes[0] > SIZE_MAX / height)
>          return AVERROR(EINVAL);
> -    size[0] = linesizes[0] * height;
> +    sizes[0] = linesizes[0] * height;

You would need to cast height to size_t for this, i think, but seeing
av_image_check_size() currently rejects line sizes and plane sizes
bigger than INT_MAX, maybe we should just keep INT_MAX in the above
check instead (No need to send a new revision for this, i can amend it
before pushing with either solution. I just want your opinion).

>  
>      if (desc->flags & AV_PIX_FMT_FLAG_PAL ||
>          desc->flags & FF_PSEUDOPAL) {
> -        data[1] = ptr + size[0]; /* palette is stored here as 256 32 bits words */
> -        return size[0] + 256 * 4;
> +        sizes[1] = 256 * 4; /* palette is stored here as 256 32 bits words */
> +        return 0;
>      }
>  
>      for (i = 0; i < 4; i++)
>          has_plane[desc->comp[i].plane] = 1;
>  
> -    total_size = size[0];
>      for (i = 1; i < 4 && has_plane[i]; i++) {
>          int h, s = (i == 1 || i == 2) ? desc->log2_chroma_h : 0;
> -        data[i] = data[i-1] + size[i-1];
>          h = (height + (1 << s) - 1) >> s;
> -        if (linesizes[i] > INT_MAX / h)
> +        if (linesizes[i] > SIZE_MAX / h)
>              return AVERROR(EINVAL);
> -        size[i] = h * linesizes[i];
> -        if (total_size > INT_MAX - size[i])
> +        sizes[i] = h * linesizes[i];

Same here.

Rest LGTM.
Brian Kim July 14, 2020, 12:19 a.m. UTC | #2
On Mon, Jul 13, 2020 at 11:22 AM James Almer <jamrial@gmail.com> wrote:
[...]
> You would need to cast height to size_t for this, i think, but seeing
> av_image_check_size() currently rejects line sizes and plane sizes
> bigger than INT_MAX, maybe we should just keep INT_MAX in the above
> check instead (No need to send a new revision for this, i can amend it
> before pushing with either solution. I just want your opinion).

If we move towards using size_t/ptrdiff_t, it seems to make sense to
use SIZE_MAX so that we do not have to come back and update this
afterwards. It seems like even if we limited the values to INT_MAX
users would think that they should check the range again anyways based
on the type.

However, I am fine with keeping it limited to INT_MAX to keep things
consistent until we can actually use the full range in other places.
James Almer July 22, 2020, 2:46 p.m. UTC | #3
On 7/13/2020 9:19 PM, Brian Kim wrote:
> On Mon, Jul 13, 2020 at 11:22 AM James Almer <jamrial@gmail.com> wrote:
> [...]
>> You would need to cast height to size_t for this, i think, but seeing
>> av_image_check_size() currently rejects line sizes and plane sizes
>> bigger than INT_MAX, maybe we should just keep INT_MAX in the above
>> check instead (No need to send a new revision for this, i can amend it
>> before pushing with either solution. I just want your opinion).
> 
> If we move towards using size_t/ptrdiff_t, it seems to make sense to
> use SIZE_MAX so that we do not have to come back and update this
> afterwards. It seems like even if we limited the values to INT_MAX
> users would think that they should check the range again anyways based
> on the type.
> 
> However, I am fine with keeping it limited to INT_MAX to keep things
> consistent until we can actually use the full range in other places.

Left it with SIZE_MAX checks and height cast to size_t, and pushed the set.

Thanks
diff mbox series

Patch

diff --git a/doc/APIchanges b/doc/APIchanges
index 1d6cc36b8c..44defd9ca8 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -15,6 +15,9 @@  libavutil:     2017-10-21
 
 API changes, most recent first:
 
+2020-07-xx - xxxxxxxxxx - lavu 56.56.100 - imgutils.h
+  Add av_image_fill_plane_sizes().
+
 2020-06-12 - b09fb030c1 - lavu 56.55.100 - pixdesc.h
   Add AV_PIX_FMT_X2RGB10.
 
diff --git a/libavutil/imgutils.c b/libavutil/imgutils.c
index 7f9c1b632c..345b7fa94c 100644
--- a/libavutil/imgutils.c
+++ b/libavutil/imgutils.c
@@ -108,45 +108,69 @@  int av_image_fill_linesizes(int linesizes[4], enum AVPixelFormat pix_fmt, int wi
     return 0;
 }
 
-int av_image_fill_pointers(uint8_t *data[4], enum AVPixelFormat pix_fmt, int height,
-                           uint8_t *ptr, const int linesizes[4])
+int av_image_fill_plane_sizes(size_t sizes[4], enum AVPixelFormat pix_fmt,
+                              int height, const ptrdiff_t linesizes[4])
 {
-    int i, total_size, size[4] = { 0 }, has_plane[4] = { 0 };
+    int i, has_plane[4] = { 0 };
 
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
-    memset(data     , 0, sizeof(data[0])*4);
+    memset(sizes    , 0, sizeof(sizes[0])*4);
 
     if (!desc || desc->flags & AV_PIX_FMT_FLAG_HWACCEL)
         return AVERROR(EINVAL);
 
-    data[0] = ptr;
-    if (linesizes[0] > (INT_MAX - 1024) / height)
+    if (linesizes[0] > SIZE_MAX / height)
         return AVERROR(EINVAL);
-    size[0] = linesizes[0] * height;
+    sizes[0] = linesizes[0] * height;
 
     if (desc->flags & AV_PIX_FMT_FLAG_PAL ||
         desc->flags & FF_PSEUDOPAL) {
-        data[1] = ptr + size[0]; /* palette is stored here as 256 32 bits words */
-        return size[0] + 256 * 4;
+        sizes[1] = 256 * 4; /* palette is stored here as 256 32 bits words */
+        return 0;
     }
 
     for (i = 0; i < 4; i++)
         has_plane[desc->comp[i].plane] = 1;
 
-    total_size = size[0];
     for (i = 1; i < 4 && has_plane[i]; i++) {
         int h, s = (i == 1 || i == 2) ? desc->log2_chroma_h : 0;
-        data[i] = data[i-1] + size[i-1];
         h = (height + (1 << s) - 1) >> s;
-        if (linesizes[i] > INT_MAX / h)
+        if (linesizes[i] > SIZE_MAX / h)
             return AVERROR(EINVAL);
-        size[i] = h * linesizes[i];
-        if (total_size > INT_MAX - size[i])
+        sizes[i] = h * linesizes[i];
+    }
+
+    return 0;
+}
+
+int av_image_fill_pointers(uint8_t *data[4], enum AVPixelFormat pix_fmt, int height,
+                           uint8_t *ptr, const int linesizes[4])
+{
+    int i, ret;
+    ptrdiff_t linesizes1[4];
+    size_t sizes[4];
+
+    for (i = 0; i < 4; i++)
+        linesizes1[i] = linesizes[i];
+
+    ret = av_image_fill_plane_sizes(sizes, pix_fmt, height, linesizes1);
+    if (ret < 0)
+        return ret;
+
+    ret = 0;
+    for (i = 0; i < 4; i++) {
+        if (sizes[i] > INT_MAX - ret)
             return AVERROR(EINVAL);
-        total_size += size[i];
+        ret += sizes[i];
     }
 
-    return total_size;
+    memset(data , 0, sizeof(data[0])*4);
+
+    data[0] = ptr;
+    for (i = 1; i < 4 && sizes[i - 1] > 0; i++)
+        data[i] = data[i - 1] + sizes[i - 1];
+
+    return ret;
 }
 
 int avpriv_set_systematic_pal2(uint32_t pal[256], enum AVPixelFormat pix_fmt)
@@ -194,6 +218,8 @@  int av_image_alloc(uint8_t *pointers[4], int linesizes[4],
 {
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
     int i, ret;
+    ptrdiff_t linesizes1[4];
+    size_t total_size, sizes[4];
     uint8_t *buf;
 
     if (!desc)
@@ -204,12 +230,20 @@  int av_image_alloc(uint8_t *pointers[4], int linesizes[4],
     if ((ret = av_image_fill_linesizes(linesizes, pix_fmt, align>7 ? FFALIGN(w, 8) : w)) < 0)
         return ret;
 
-    for (i = 0; i < 4; i++)
+    for (i = 0; i < 4; i++) {
         linesizes[i] = FFALIGN(linesizes[i], align);
+        linesizes1[i] = linesizes[i];
+    }
 
-    if ((ret = av_image_fill_pointers(pointers, pix_fmt, h, NULL, linesizes)) < 0)
+    if ((ret = av_image_fill_plane_sizes(sizes, pix_fmt, h, linesizes1)) < 0)
         return ret;
-    buf = av_malloc(ret + align);
+    total_size = align;
+    for (i = 0; i < 4; i++) {
+        if (total_size > SIZE_MAX - sizes[i])
+            return AVERROR(EINVAL);
+        total_size += sizes[i];
+    }
+    buf = av_malloc(total_size);
     if (!buf)
         return AVERROR(ENOMEM);
     if ((ret = av_image_fill_pointers(pointers, pix_fmt, h, buf, linesizes)) < 0) {
@@ -220,6 +254,7 @@  int av_image_alloc(uint8_t *pointers[4], int linesizes[4],
         avpriv_set_systematic_pal2((uint32_t*)pointers[1], pix_fmt);
         if (align < 4) {
             av_log(NULL, AV_LOG_ERROR, "Formats with a palette require a minimum alignment of 4\n");
+            av_free(buf);
             return AVERROR(EINVAL);
         }
     }
@@ -431,9 +466,10 @@  int av_image_fill_arrays(uint8_t *dst_data[4], int dst_linesize[4],
 int av_image_get_buffer_size(enum AVPixelFormat pix_fmt,
                              int width, int height, int align)
 {
-    uint8_t *data[4];
+    int ret, i;
     int linesize[4];
-    int ret;
+    ptrdiff_t aligned_linesize[4];
+    size_t sizes[4];
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
     if (!desc)
         return AVERROR(EINVAL);
@@ -446,8 +482,24 @@  int av_image_get_buffer_size(enum AVPixelFormat pix_fmt,
     if (desc->flags & FF_PSEUDOPAL)
         return FFALIGN(width, align) * height;
 
-    return av_image_fill_arrays(data, linesize, NULL, pix_fmt,
-                                width, height, align);
+    ret = av_image_fill_linesizes(linesize, pix_fmt, width);
+    if (ret < 0)
+        return ret;
+
+    for (i = 0; i < 4; i++)
+        aligned_linesize[i] = FFALIGN(linesize[i], align);
+
+    ret = av_image_fill_plane_sizes(sizes, pix_fmt, height, aligned_linesize);
+    if (ret < 0)
+      return ret;
+
+    ret = 0;
+    for (i = 0; i < 4; i++) {
+        if (sizes[i] > INT_MAX - ret)
+            return AVERROR(EINVAL);
+        ret += sizes[i];
+    }
+    return ret;
 }
 
 int av_image_copy_to_buffer(uint8_t *dst, int dst_size,
diff --git a/libavutil/imgutils.h b/libavutil/imgutils.h
index 5b790ecf0a..b09ca11e90 100644
--- a/libavutil/imgutils.h
+++ b/libavutil/imgutils.h
@@ -67,6 +67,17 @@  int av_image_get_linesize(enum AVPixelFormat pix_fmt, int width, int plane);
  */
 int av_image_fill_linesizes(int linesizes[4], enum AVPixelFormat pix_fmt, int width);
 
+/**
+ * Fill plane sizes for an image with pixel format pix_fmt and height height.
+ *
+ * @param size the array to be filled with the size of each image plane
+ * @param linesizes the array containing the linesize for each
+ * plane, should be filled by av_image_fill_linesizes()
+ * @return >= 0 in case of success, a negative error code otherwise
+ */
+int av_image_fill_plane_sizes(size_t size[4], enum AVPixelFormat pix_fmt,
+                              int height, const ptrdiff_t linesizes[4]);
+
 /**
  * Fill plane data pointers for an image with pixel format pix_fmt and
  * height height.
diff --git a/libavutil/version.h b/libavutil/version.h
index 3ce9b1831e..a63f79feb1 100644
--- a/libavutil/version.h
+++ b/libavutil/version.h
@@ -79,7 +79,7 @@ 
  */
 
 #define LIBAVUTIL_VERSION_MAJOR  56
-#define LIBAVUTIL_VERSION_MINOR  55
+#define LIBAVUTIL_VERSION_MINOR  56
 #define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \