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avdevice/v4l2: fix potential memleak when allocating device buffers

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In the loop which allocates the buffers for a V4L2 device, if failure
occurs for a certain buffer (e.g. 3rd of 4 buffers), then the previously
allocated buffers (and the buffer array) would not be free'd in
the mmap_init(). This would cause a leak.

This change handles the error cases of that loop to free all allocated
resources, so that when mmap_init() fails nothing is leaked.

Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
This commit is contained in:
Alexandru Ardelean
2026-04-09 16:01:11 +03:00
committed by Ramiro Polla
parent 0e983a0604
commit 24adcf3a72
1 changed files with 20 additions and 10 deletions
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30
libavdevice/v4l2.c
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@@ -356,6 +356,15 @@ static void list_standards(AVFormatContext *ctx)
}
}
static void mmap_free(struct video_data *s, int n)
{
while (--n > 0) {
v4l2_munmap(s->buf_start[n], s->buf_len[n]);
}
av_freep(&s->buf_start);
av_freep(&s->buf_len);
}
static int mmap_init(AVFormatContext *ctx)
{
int i, res;
@@ -402,13 +411,14 @@ static int mmap_init(AVFormatContext *ctx)
if (v4l2_ioctl(s->fd, VIDIOC_QUERYBUF, &buf) < 0) {
res = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYBUF): %s\n", av_err2str(res));
return res;
goto fail;
}
if (s->multiplanar) {
if (buf.length != 1) {
av_log(ctx, AV_LOG_ERROR, "multiplanar only supported when buf.length == 1\n");
return AVERROR_PATCHWELCOME;
res = AVERROR_PATCHWELCOME;
goto fail;
}
buf_length = buf.m.planes[0].length;
buf_offset = buf.m.planes[0].m.mem_offset;
@@ -422,7 +432,8 @@ static int mmap_init(AVFormatContext *ctx)
av_log(ctx, AV_LOG_ERROR,
"buf_len[%d] = %d < expected frame size %d\n",
i, s->buf_len[i], s->frame_size);
return AVERROR(ENOMEM);
res = AVERROR(ENOMEM);
goto fail;
}
s->buf_start[i] = v4l2_mmap(NULL, buf_length,
PROT_READ | PROT_WRITE, MAP_SHARED,
@@ -431,11 +442,15 @@ static int mmap_init(AVFormatContext *ctx)
if (s->buf_start[i] == MAP_FAILED) {
res = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "mmap: %s\n", av_err2str(res));
return res;
goto fail;
}
}
return 0;
fail:
mmap_free(s, i);
return res;
}
static int enqueue_buffer(struct video_data *s, struct v4l2_buffer *buf)
@@ -681,18 +696,13 @@ static int mmap_start(AVFormatContext *ctx)
static void mmap_close(struct video_data *s)
{
enum v4l2_buf_type type;
int i;
type = s->buf_type;
/* We do not check for the result, because we could
* not do anything about it anyway...
*/
v4l2_ioctl(s->fd, VIDIOC_STREAMOFF, &type);
for (i = 0; i < s->buffers; i++) {
v4l2_munmap(s->buf_start[i], s->buf_len[i]);
}
av_freep(&s->buf_start);
av_freep(&s->buf_len);
mmap_free(s, s->buffers);
}
static int v4l2_set_parameters(AVFormatContext *ctx)