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Static analysis reveals that tok_mode->last_expr_buffer[i] != '\0' && i < input_length is not safe #132769

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sobolevn opened this issue Apr 21, 2025 · 0 comments
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Static analysis reveals that tok_mode->last_expr_buffer[i] != '\0' && i < input_length is not safe #132769

sobolevn opened this issue Apr 21, 2025 · 0 comments
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interpreter-core (Objects, Python, Grammar, and Parser dirs) topic-parser type-bug An unexpected behavior, bug, or error

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sobolevn commented Apr 21, 2025 •
edited by bedevere-app bot
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Bug report

This code can be improved:

cpython/Parser/lexer/lexer.c

Line 143 in 132b6bc

while (tok_mode->last_expr_buffer[i] != '\0' && i < input_length) {

It would be safer to first check the value of i and then try to access [i] index. This way it is harder to get read out of bounds.

Found by PVS-Studio in https://habr.com/ru/companies/pvs-studio/articles/902048/

Linked PRs
@sobolevn sobolevn added interpreter-core (Objects, Python, Grammar, and Parser dirs) topic-parser type-bug An unexpected behavior, bug, or error labels Apr 21, 2025
@sobolevn sobolevn self-assigned this Apr 21, 2025
sobolevn added a commit to sobolevn/cpython that referenced this issue Apr 21, 2025
@sobolevn
pythongh-132769: Refactor possible read-out-of-bounds in lexer.c
a7f914d
@bedevere-app bedevere-app bot mentioned this issue Apr 21, 2025
Merged
sobolevn added a commit to sobolevn/cpython that referenced this issue Apr 21, 2025
@sobolevn
pythongh-132769: Refactor possible read-out-of-bounds in lexer.c
8768865
pablogsal pushed a commit that referenced this issue Apr 21, 2025
@sobolevn
gh-132769: Refactor possible read-out-of-bounds in lexer.c (#132770)
ea8ec95
miss-islington pushed a commit to miss-islington/cpython that referenced this issue Apr 21, 2025
@sobolevn @miss-islington
pythongh-132769: Refactor possible read-out-of-bounds in lexer.c (p…
b19205b 
…ythonGH-132770)

(cherry picked from commit ea8ec95)

Co-authored-by: sobolevn <[email protected]>
@bedevere-app bedevere-app bot mentioned this issue Apr 21, 2025
Merged
sobolevn added a commit that referenced this issue Apr 21, 2025
@miss-islington @sobolevn
[3.13] gh-132769: Refactor possible read-out-of-bounds in lexer.c (G…
e140e6e 
…H-132770) (#132788)

gh-132769: Refactor possible read-out-of-bounds in `lexer.c` (GH-132770)
(cherry picked from commit ea8ec95)

Co-authored-by: sobolevn <[email protected]>
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