Stack cookie enhancements #119
Merged
Conversation
This file contains 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
Generalise the bit rotation implementations to use a common macro, and add roll() and rorl() to handle unsigned long values. Each function will still compile down to a single instruction. Signed-off-by: Michael Brown <mcb30@ipxe.org>
Several of the values used to compute a stack cookie (in the absence of a viable entropy source) will tend to have either all-zeroes or all-ones in the higher order bits. Rotate the values in order to distribute the (minimal) available entropy more evenly. Suggested-by: Pete Beck <pete.beck@ioactive.com> Signed-off-by: Michael Brown <mcb30@ipxe.org>
The NUL byte included within the stack cookie to act as a string terminator should be placed at the lowest byte address within the stack cookie, in order to avoid potentially including the stack cookie value within an accidentally unterminated string. Suggested-by: Pete Beck <pete.beck@ioactive.com> Signed-off-by: Michael Brown <mcb30@ipxe.org>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
No description provided.