Fix sscanf return value checks in cgroups#28
Open
odaysec wants to merge 1 commit into
Open
Conversation
Ensure sscanf checks return value for Buffers, Cached, and MemAvailable.
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
1 participant
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
Ensure sscanf checks return value for Buffers, Cached, and MemAvailable. scanf‑like functions should have their return values compared against the exact number of expected assignments (here,
1), rather than simply tested for non‑zero. This ensures that partial matches, mismatches, or any other non‑successful cases are properly ignored.In this file, the first four
sscanfcalls already use== 1. The last three ("Buffers","Cached","MemAvailable") are used asif (sscanf(...)), which only checks for non‑zero. To align with the recommended pattern without changing functionality, update those three conditions to explicitly check== 1. Concretely, inlibmemory-patches/cgroups.caround lines 639–643, change:else if (sscanf(line, "Buffers: %llu", &value))→else if (sscanf(line, "Buffers: %llu", &value) == 1)else if (sscanf(line, "Cached: %llu", &value))→else if (sscanf(line, "Cached: %llu", &value) == 1)else if (sscanf(line, "MemAvailable: %llu", &value))→else if (sscanf(line, "MemAvailable: %llu", &value) == 1)References
SEI CERT C++ Coding Standard: ERR62-CPP. Detect errors when converting a string to a number
SEI CERT C Coding Standard: ERR33-C. Detect and handle standard library errors
cppreference.com: scanf, fscanf, sscanf, scanf_s, fscanf_s, sscanf_s.