Fix #71848: getimagesize with $imageinfo returns false#3319
Closed
cmb69 wants to merge 1 commit intophp:PHP-7.1from
Closed
Fix #71848: getimagesize with $imageinfo returns false#3319cmb69 wants to merge 1 commit intophp:PHP-7.1from
cmb69 wants to merge 1 commit intophp:PHP-7.1from
Conversation
Some JFIF images contain empty APP segments, i.e. those which consist only of the marker bytes and the length, but without actual content. It appears to be doubtful to have empty APP segments, but we should apply the robustness principle, and accept these, instead of simply failing in this case. We choose to add empty APP segments to $imageinfo with an empty string as value, instead of NULL, or even to omit these segments altogether. This patch also fixes the potential issue that php_stream_read() might not read the supposed number of bytes, which could result in garbage to be added to the read value.
Member
Author
|
If nobody objects, I'm going to merge this PR during the weekend. |
|
Comment on behalf of cmb at php.net: Applied via ae04110 and merged up. |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Some JFIF images contain empty APP segments, i.e. those which consist
only of the marker bytes and the length, but without actual content.
It appears to be doubtful to have empty APP segments, but we should
apply the robustness principle, and accept these, instead of simply
failing in this case.
We choose to add empty APP segments to $imageinfo with an empty string
as value, instead of NULL, or even to omit these segments altogether.
This patch also fixes the potential issue that php_stream_read() might
not read the supposed number of bytes, which could result in garbage to
be added to the read value.
As far as I know, php_stream_read() returns the actual number of bytes read, and may read less bytes than requested. If so, checking the result for
<= 0would not be correct anyway. Please correct me if I'm wrong.Regarding the decision to add an empty string instead of NULL: this is somewhat arbitrary, given that the meaning of empty APP segments is not clear, but it is the simplest fix, and is certainly not completely illogical.