/ 
Imager-1.036
⭐ Starred 27 / Imager::Preprocess
Security Advisories (3)
CVE-2026-102504 (2026-10-01)

Imager versions before 1.037 for Perl exit the process reading a raw image with an out-of-range raw_datachannels value in i_readraw_wiol. Nothing range-checks raw_datachannels. The line buffer is sized as the image width times the channel count with no overflow check, so a negative or very large count requests an excessive allocation. When it fails, Imager's allocator calls exit(3). Passing an untrusted raw_datachannels value to Imager->read() triggers an uncatchable exit.

CVE-2026-102505 (2026-10-01)

Imager versions before 1.037 for Perl overflow a heap buffer fetching float samples from a paletted image in i_gsampf_fp. For a paletted image, getsamples() with type "float" allocates a buffer of one sample per pixel and fetches every requested channel of each pixel into it. Requesting more than one channel writes past its end. An attacker-supplied image controls the overflowing bytes through its palette.

CVE-2026-112202 (2026-10-20)

Imager::File::GIF versions before 1.006 for Perl allow out-of-bounds reads when consolidating GIF images. With `gif_consolidate => 1`, palette indices from the image are used without checking the colour table's bounds. The i_readgif_low routine reads beyond the heap allocation and copies the bytes into output pixels. The default GIF reader is not affected. The same code ships bundled in the Imager distribution. An attacker supplying a crafted GIF can disclose adjacent heap memory through the decoded output and may crash the process.

NAME

Imager::Preprocess - simple preprocessor for handling multiple sample sizes

SYNOPSIS

/* in the source: */
#code condition true to work with 8-bit samples
... code using preprocessor types/values ...
#/code

# process and make #line directives
perl -MImager::Preprocess -epreprocess foo.im foo.c

# process and no #line directives
perl -MImager::Preprocess -epreprocess -l foo.im foo.c

DESCRIPTION

This is a simple preprocessor that aims to reduce duplication of source code when implementing an algorithm both for 8-bit samples and double samples in Imager.

Imager's Makefile.PL currently scans the MANIFEST for .im files and adds Makefile files to convert these to .c files.

The beginning of a sample-independent section of code is preceded by:

#code expression

where expression should return true if processing should be done at 8-bits/sample.

You can also use a #code block around a function definition to produce 8-bit and double sample versions of a function. In this case #code has no expression and you will need to use IM_SUFFIX() to produce different function names.

The end of a sample-independent section of code is terminated by:

#/code

#code sections cannot be nested.

#/code without a starting #code is an error.

You can also define extra sample-size dependent macros with #!define:

#define common-name eight-bit-name floating-point-name

The following types and values are defined in a #code section:

  • IM_GPIX(im, x, y, &col)

  • IM_GLIN(im, l, r, y, colors)

  • IM_PPIX(im, x, y, &col)

  • IM_PLIN(im, x, y, colors)

  • IM_GSAMP(im, l, r, y, samples, chans, chan_count)

    These correspond to the appropriate image function, eg. IM_GPIX() becomes i_gpix() or i_gpixf() as appropriate.

  • IM_ADAPT_COLORS(dest_channels, src_channels, colors, count)

    Call i_adapt_colors() or i_adapt_fcolors().

  • IM_FILL_COMBINE(fill) - retrieve the combine function from a fill object.

  • IM_FILL_FILLER(fill) - retrieve the fill_with_* function from a fill object.

  • IM_ABS(sample) - calculate the absolute value of an IM_WORK_T value.

  • IM_SAMPLE_MAX - maximum value for a sample

  • IM_SAMPLE_MAX2 - maximum value for a sample, squared

  • IM_SAMPLE_T - type of a sample (i_sample_t or i_fsample_t)

  • IM_COLOR - color type, either i_color or i_fcolor.

  • IM_WORK_T - working sample type, either int or double.

  • IM_Sf - format string for the sample type, "%d" or "%f".

  • IM_Wf - format string for the work type, "%d" or "%f".

  • IM_SUFFIX(identifier) - adds _8 or _double onto the end of identifier.

  • IM_EIGHT_BIT - this is a macro defined only in 8-bit/sample code.

Other types, functions and values may be added in the future.

AUTHOR

Tony Cook <tonyc@cpan.org>