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Self-reference to $this in PelIfd::$maker_notes #6

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saemy opened this issue Oct 4, 2023 · 2 comments · May be fixed by #7
Open

Self-reference to $this in PelIfd::$maker_notes #6

saemy opened this issue Oct 4, 2023 · 2 comments · May be fixed by #7

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@saemy
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saemy commented Oct 4, 2023

PelIfd::$maker_notes["parent"] is always $this (there is only one caller of PelIfd::setMakerNotes()). However, adding $this to the array leads to a reference of a PelIfd instance to itself. As a result that PelIfd instance can not be cleaned up right away after all references to it go away (as the ref_count remains at 1 - the one to itself). Only at garbage collection time the garbage cycle is detected and that instance is cleaned up.

This is an issue in case big images are processed one after another. In that scenario PelIfd::$maker_notes['data'] contains the full image data (i.e. multiple MB) and is only released upon garbage collection time - which is not right away. Garbage memory is piling up and running out of memory is easily possible and the program might crash with "Fatal error: Allowed memory size of xxx bytes exhausted".
saemy added a commit to saemy/pel that referenced this issue Oct 4, 2023
@saemy
Remove self-reference in PelIfd::$maker_notes
fcbef36 
`PelIfd::$maker_notes["parent"]` is always `$this` (there is only one caller of
`PelIfd::setMakerNotes()`). However, adding `$this` to the array leads to a
reference of a `PelIfd` instance to itself. As a result that `PelIfd` instance
can not be cleaned up right away after all references to it go away (as the
ref_count remains at 1 - the one to itself).
Only at garbage collection time the garbage cycle is detected and that instance
is cleaned up.

This is an issue in case big images are processed one after another. In that
scenario `PelIfd::$maker_notes['data']` contains the full image data (i.e.
multiple MB) and is only released upon garbage collection time - which is not
right away. Garbage memory is piling up and running out of memory is easily
possible and the program might crash with `"Fatal error:  Allowed memory size
of xxx bytes exhausted"`.

Removes the self-reference in the `PelIfd::$maker_notes` array.

fixes: FileEye#6
@saemy saemy linked a pull request Oct 4, 2023 that will close this issue
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@devbranch-vitaliy
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devbranch-vitaliy commented Dec 5, 2023 •
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The same thing!
I tried to fix the issue with #7 but it didn't help me, the issue is still reproducible
In my case, more than 15 Jpeg images are processed one after another.
At the very least, we must provide protection against an infinite loop.

@saemy
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saemy commented Dec 12, 2023 •
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@devbranch-vitaliy Can you share one of those images s.t. I can try to reproduce? Thank you.

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Remove self-reference in PelIfd::$maker_notes saemy/pel
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@saemy @devbranch-vitaliy