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Add WebP support to ext/exif #22213

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62 changes: 61 additions & 1 deletion ext/exif/exif.c
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Original file line number Diff line number Diff line change
Expand Up @@ -69,7 +69,7 @@ PHP_MINFO_FUNCTION(exif)
php_info_print_table_start();
php_info_print_table_row(2, "EXIF Support", "enabled");
php_info_print_table_row(2, "Supported EXIF Version", "0220");
php_info_print_table_row(2, "Supported filetypes", "JPEG, TIFF");
php_info_print_table_row(2, "Supported filetypes", "JPEG, TIFF, HEIF, WebP");

if (USE_MBSTRING) {
php_info_print_table_row(2, "Multibyte decoding support using mbstring", "enabled");
Expand Down Expand Up @@ -4445,6 +4445,55 @@ static bool exif_scan_HEIF_header(image_info_type *ImageInfo, unsigned char *buf
return ret;
}

static bool exif_scan_WEBP_header(image_info_type *ImageInfo, size_t riff_size)
{
/* "Exif\0\0" identifier code */
static const uchar ExifHeader[] = {0x45, 0x78, 0x69, 0x66, 0x00, 0x00};
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@Girgias Girgias Jun 5, 2026

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Could you add a commment explaining this? As looking from the spec it's not immediately obvious why this is the corresponding Exif header? Or is this just {'E', 'X', 'I', 'F', 0, 0}? In which chase writting it that way would be more obvious. Not everyone knows ASCII by heart.

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@iliaal iliaal Jun 5, 2026

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Added a comment. It's the Exif\0\0 identifier code, the same array as in exif_process_APP1, so I kept the hex form to match it.

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@iliaal iliaal Jun 5, 2026

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Alternatively, I can update both places to admittedly more clear {'E', 'X', 'I', 'F', 0, 0}, just doesn't make sense to do the same thing in 2 different ways (imho)

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@Girgias Girgias Jun 6, 2026

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I think it makes sense to do so in a follow-up PR to update both places.

unsigned char chunk_header[8];
size_t offset = 12;
size_t riff_end = riff_size <= ImageInfo->FileSize - 8 ? riff_size + 8 : ImageInfo->FileSize;

while (offset + 8 <= riff_end) {
if ((php_stream_seek(ImageInfo->infile, offset, SEEK_SET) < 0) ||
(exif_read_from_stream_file_looped(ImageInfo->infile, (char*)chunk_header, 8) != 8)) {
return false;
}

size_t chunk_size = php_ifd_get32u(chunk_header + 4, 0);
size_t payload_offset = offset + 8;

if (chunk_size > riff_end - payload_offset) {
return false;
}

if (!memcmp(chunk_header, "EXIF", 4)) {
char *data;
size_t skip = 0;
bool ret = false;

if (chunk_size < 8) {
return false;
}

data = emalloc(chunk_size);
Comment on lines +4470 to +4478
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@Girgias Girgias Jun 6, 2026

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nit:

Suggested change
char *data;
size_t skip = 0;
bool ret = false;
if (chunk_size < 8) {
return false;
}
data = emalloc(chunk_size);
size_t skip = 0;
bool ret = false;
if (chunk_size < 8) {
return false;
}
char *data = emalloc(chunk_size);

if (exif_read_from_stream_file_looped(ImageInfo->infile, data, chunk_size) == chunk_size) {
if (chunk_size >= sizeof(ExifHeader) + 8 && !memcmp(data, ExifHeader, sizeof(ExifHeader))) {
skip = sizeof(ExifHeader);
}
exif_process_TIFF_in_JPEG(ImageInfo, data + skip, chunk_size - skip, payload_offset + skip);
ret = true;
}
efree(data);
return ret;
}

/* RIFF chunks are word-aligned: an odd payload is followed by a pad byte. */
offset = payload_offset + chunk_size + (chunk_size & 1);
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}

return false;
}

/* {{{ exif_scan_FILE_header
* Parse the marker stream until SOS or EOI is seen; */
static bool exif_scan_FILE_header(image_info_type *ImageInfo)
Expand Down Expand Up @@ -4521,6 +4570,17 @@ static bool exif_scan_FILE_header(image_info_type *ImageInfo)
exif_error_docref(NULL EXIFERR_CC, ImageInfo, E_WARNING, "Invalid HEIF file");
return false;
}
} else if ((ImageInfo->FileSize >= 16) &&
(!memcmp(file_header, "RIFF", 4)) &&
(exif_read_from_stream_file_looped(ImageInfo->infile, (char*)(file_header + 8), 4) == 4) &&
(!memcmp(file_header + 8, "WEBP", 4))) {
if (exif_scan_WEBP_header(ImageInfo, php_ifd_get32u(file_header + 4, 0))) {
ImageInfo->FileType = IMAGE_FILETYPE_WEBP;
return true;
} else {
exif_error_docref(NULL EXIFERR_CC, ImageInfo, E_WARNING, "Invalid WebP file");
return false;
}
} else {
exif_error_docref(NULL EXIFERR_CC, ImageInfo, E_WARNING, "File not supported");
return false;
Expand Down
82 changes: 82 additions & 0 deletions ext/exif/tests/gh19904.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,82 @@
--TEST--
GH-19904 (exif_read_data() reads EXIF metadata from WebP images)
--EXTENSIONS--
exif
--INI--
output_handler=
zlib.output_compression=0
--FILE--
<?php
var_dump(exif_read_data(__DIR__.'/gh19904.webp'));
?>
--EXPECTF--
array(26) {
["FileName"]=>
string(12) "gh19904.webp"
["FileDateTime"]=>
int(%d)
["FileSize"]=>
int(526)
["FileType"]=>
int(18)
["MimeType"]=>
string(10) "image/webp"
["SectionsFound"]=>
string(24) "ANY_TAG, IFD0, EXIF, GPS"
["COMPUTED"]=>
array(4) {
["IsColor"]=>
int(0)
["ByteOrderMotorola"]=>
int(0)
["UserComment"]=>
string(17) "Created with GIMP"
["UserCommentEncoding"]=>
string(9) "UNDEFINED"
}
["ImageWidth"]=>
int(100)
["ImageLength"]=>
int(100)
["BitsPerSample"]=>
array(3) {
[0]=>
int(8)
[1]=>
int(8)
[2]=>
int(8)
}
["ImageDescription"]=>
string(17) "Created with GIMP"
["XResolution"]=>
string(5) "300/1"
["YResolution"]=>
string(5) "300/1"
["ResolutionUnit"]=>
int(2)
["Software"]=>
string(10) "GIMP 3.0.4"
["DateTime"]=>
string(19) "2025:09:21 15:30:30"
["Exif_IFD_Pointer"]=>
int(250)
["GPS_IFD_Pointer"]=>
int(430)
["DateTimeOriginal"]=>
string(19) "2025:09:21 15:29:27"
["DateTimeDigitized"]=>
string(19) "2025:09:21 15:29:27"
["OffsetTime"]=>
string(6) "+02:00"
["OffsetTimeOriginal"]=>
string(6) "+02:00"
["OffsetTimeDigitized"]=>
string(6) "+02:00"
["UserComment"]=>
string(25) "%sCreated with GIMP"
["ColorSpace"]=>
int(1)
["GPSAltitude"]=>
string(5) "0/100"
}
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