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Simplified API: write-to-memory, overflow handling

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This implements an API and provides a number of assist macros to allow an
application which uses the simplified API write to bypass stdio and write
directly to memory.

It also includes some warnings (png.h) and some check code to detect *possible*
overflow in the ROW_STRIDE and simplified image SIZE macros.  This disallows
image width/height/format that *might* overflow.  A quiet API change that limits
in-memory image size (uncompressed) to less that 4GByte and image row size
(stride) to less than 2GByte.

Signed-off-by: John Bowler <jbowler@acm.org>
This commit is contained in:
John Bowler
2016-01-18 09:53:38 -08:00
parent 777dbf46dc
commit 175a126a1a
7 changed files with 391 additions and 63 deletions
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61
contrib/libtests/pngstest.c
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@@ -307,7 +307,7 @@ compare_16bit(int v1, int v2, int error_limit, int multiple_algorithms)
}
#endif /* unused */
#define READ_FILE 1 /* else memory */
#define USE_FILE 1 /* else memory */
#define USE_STDIO 2 /* else use file name */
#define STRICT 4 /* fail on warnings too */
#define VERBOSE 8
@@ -320,7 +320,7 @@ compare_16bit(int v1, int v2, int error_limit, int multiple_algorithms)
static void
print_opts(png_uint_32 opts)
{
if (opts & READ_FILE)
if (opts & USE_FILE)
printf(" --file");
if (opts & USE_STDIO)
printf(" --stdio");
@@ -3008,14 +3008,14 @@ read_file(Image *image, png_uint_32 format, png_const_colorp background)
static int
read_one_file(Image *image)
{
if (!(image->opts & READ_FILE) || (image->opts & USE_STDIO))
if (!(image->opts & USE_FILE) || (image->opts & USE_STDIO))
{
/* memory or stdio. */
FILE *f = fopen(image->file_name, "rb");
if (f != NULL)
{
if (image->opts & READ_FILE)
if (image->opts & USE_FILE)
image->input_file = f;
else /* memory */
@@ -3096,6 +3096,7 @@ write_one_file(Image *output, Image *image, int convert_to_8bit)
if (image->opts & USE_STDIO)
{
#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
#ifndef __COVERITY__
FILE *f = tmpfile();
#else
@@ -3158,10 +3159,14 @@ write_one_file(Image *output, Image *image, int convert_to_8bit)
else
return logerror(image, "tmpfile", ": open: ", strerror(errno));
#else /* SIMPLIFIED_WRITE_STDIO */
return logerror(image, "tmpfile", ": open: unsupported", "");
#endif /* SIMPLIFIED_WRITE_STDIO */
}
else
else if (image->opts & USE_FILE)
{
#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
static int counter = 0;
char name[32];
@@ -3181,6 +3186,48 @@ write_one_file(Image *output, Image *image, int convert_to_8bit)
else
return logerror(image, name, ": write failed", "");
#else /* SIMPLIFIED_WRITE_STDIO */
return logerror(image, "stdio", ": open: unsupported", "");
#endif /* SIMPLIFIED_WRITE_STDIO */
}
else /* use memory */
{
png_alloc_size_t size;
if (png_image_write_get_memory_size(image->image, size, convert_to_8bit,
image->buffer+16, (png_int_32)image->stride, image->colormap))
{
/* This is non-fatal: */
if (size > PNG_IMAGE_PNG_SIZE_MAX(image->image))
logerror(image, "memory", ": PNG_IMAGE_SIZE_MAX wrong", "");
initimage(output, image->opts, "memory", image->stride_extra);
output->input_memory = malloc(size);
if (output->input_memory != NULL)
{
output->input_memory_size = size;
if (png_image_write_to_memory(&image->image, output->input_memory,
&output->input_memory_size, convert_to_8bit, image->buffer+16,
(png_int_32)image->stride, image->colormap))
{
/* This is also non-fatal (maybe): */
if (size != output->input_memory_size)
logerror(image, "memory", ": memory size wrong", "");
}
else
return logerror(image, "memory", ": write failed", "");
}
else
return logerror(image, "memory", ": out of memory", "");
}
else
return logerror(image, "memory", ": get size:", "");
}
/* 'output' has an initialized temporary image, read this back in and compare
@@ -3421,12 +3468,12 @@ main(int argc, char **argv)
}
else if (strcmp(arg, "--file") == 0)
# ifdef PNG_STDIO_SUPPORTED
opts |= READ_FILE;
opts |= USE_FILE;
# else
return 77; /* skipped: no support */
# endif
else if (strcmp(arg, "--memory") == 0)
opts &= ~READ_FILE;
opts &= ~USE_FILE;
else if (strcmp(arg, "--stdio") == 0)
# ifdef PNG_STDIO_SUPPORTED
opts |= USE_STDIO;