diff: Fix inline:char crash when using 4+ buffers #17805
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Fix an array out of bounds crash when using diffopt+=inline:char when 4 or more buffers are being diff'ed. This happens when one of the blocks is empty. The inline highlight logic skips using that buffer's block, but when another buffer is used later and calls diff_read() to merge the diff blocks together, it could erroneously consider the empty block's diff info which has not been initialized, leaving to diff numbers that are invalid. Later on the diff num is used without bounds checking which leads to the crash. Fix this by making sure to unset tp_diffbuf to NULL when we skip a block, so diff_read() will not consider this buffer to be used within inline diff. Also, add more bounds checking just to be safe.
Contributor
Author
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Credit to Ilya Grigoriev for finding this issue. |
Member
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thanks |
Contributor
Author
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@zeertzjq Probably should merge this to Neovim to address a crash in inline highlight. |
zeertzjq
added a commit
to zeertzjq/neovim
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Jul 20, 2025
Problem: Crash when using inline diff mode
(Ilya Grigoriev)
Solution: Set tp_diffbuf to NULL when skipping a diff block
(Yee Cheng Chin).
Fix an array out of bounds crash when using diffopt+=inline:char when 4
or more buffers are being diff'ed. This happens when one of the blocks
is empty. The inline highlight logic skips using that buffer's block,
but when another buffer is used later and calls diff_read() to merge the
diff blocks together, it could erroneously consider the empty block's
diff info which has not been initialized, leaving to diff numbers that
are invalid. Later on the diff num is used without bounds checking which
leads to the crash.
Fix this by making sure to unset tp_diffbuf to NULL when we skip a
block, so diff_read() will not consider this buffer to be used within
inline diff. Also, add more bounds checking just to be safe.
closes: vim/vim#17805
vim/vim@c8b99e2
Co-authored-by: Yee Cheng Chin <[email protected]>
zeertzjq
added a commit
to neovim/neovim
that referenced
this pull request
Jul 20, 2025
Problem: Crash when using inline diff mode
(Ilya Grigoriev)
Solution: Set tp_diffbuf to NULL when skipping a diff block
(Yee Cheng Chin).
Fix an array out of bounds crash when using diffopt+=inline:char when 4
or more buffers are being diff'ed. This happens when one of the blocks
is empty. The inline highlight logic skips using that buffer's block,
but when another buffer is used later and calls diff_read() to merge the
diff blocks together, it could erroneously consider the empty block's
diff info which has not been initialized, leaving to diff numbers that
are invalid. Later on the diff num is used without bounds checking which
leads to the crash.
Fix this by making sure to unset tp_diffbuf to NULL when we skip a
block, so diff_read() will not consider this buffer to be used within
inline diff. Also, add more bounds checking just to be safe.
closes: vim/vim#17805
vim/vim@c8b99e2
Co-authored-by: Yee Cheng Chin <[email protected]>
AungMyoKyaw
pushed a commit
to AungMyoKyaw/neovim
that referenced
this pull request
Jul 20, 2025
Problem: Crash when using inline diff mode
(Ilya Grigoriev)
Solution: Set tp_diffbuf to NULL when skipping a diff block
(Yee Cheng Chin).
Fix an array out of bounds crash when using diffopt+=inline:char when 4
or more buffers are being diff'ed. This happens when one of the blocks
is empty. The inline highlight logic skips using that buffer's block,
but when another buffer is used later and calls diff_read() to merge the
diff blocks together, it could erroneously consider the empty block's
diff info which has not been initialized, leaving to diff numbers that
are invalid. Later on the diff num is used without bounds checking which
leads to the crash.
Fix this by making sure to unset tp_diffbuf to NULL when we skip a
block, so diff_read() will not consider this buffer to be used within
inline diff. Also, add more bounds checking just to be safe.
closes: vim/vim#17805
vim/vim@c8b99e2
Co-authored-by: Yee Cheng Chin <[email protected]>
Contributor
|
Thank you very much for fixing it! |
dundargoc
pushed a commit
to dundargoc/neovim
that referenced
this pull request
Sep 27, 2025
Problem: Crash when using inline diff mode
(Ilya Grigoriev)
Solution: Set tp_diffbuf to NULL when skipping a diff block
(Yee Cheng Chin).
Fix an array out of bounds crash when using diffopt+=inline:char when 4
or more buffers are being diff'ed. This happens when one of the blocks
is empty. The inline highlight logic skips using that buffer's block,
but when another buffer is used later and calls diff_read() to merge the
diff blocks together, it could erroneously consider the empty block's
diff info which has not been initialized, leaving to diff numbers that
are invalid. Later on the diff num is used without bounds checking which
leads to the crash.
Fix this by making sure to unset tp_diffbuf to NULL when we skip a
block, so diff_read() will not consider this buffer to be used within
inline diff. Also, add more bounds checking just to be safe.
closes: vim/vim#17805
vim/vim@c8b99e2
Co-authored-by: Yee Cheng Chin <[email protected]>
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Fix an array out of bounds crash when using diffopt+=inline:char when 4 or more buffers are being diff'ed. This happens when one of the blocks is empty. The inline highlight logic skips using that buffer's block, but when another buffer is used later and calls diff_read() to merge the diff blocks together, it could erroneously consider the empty block's diff info which has not been initialized, leaving to diff numbers that are invalid. Later on the diff num is used without bounds checking which leads to the crash.
Fix this by making sure to unset tp_diffbuf to NULL when we skip a block, so diff_read() will not consider this buffer to be used within inline diff. Also, add more bounds checking just to be safe.
Edit: Original issue that added this crash: #16881.