password_verify() failed to verify bcrypt passwords containing null bytes
Open
Nobody has claimed this yet.
Bug
Extension: standard
Status: Needs Triage
- Dominant language
- C
- Stars
- 40.4k
- Forks
- 8.1k
- Avg merge
- 2d 13h
- Merged PRs (30d)
- 96
Description
Description
The following code:
<?php
$hash = password_hash("secret", PASSWORD_BCRYPT);
var_dump(password_verify("secret", $hash));
var_dump(password_verify("secret" . chr(0) . "suffix", $hash));
?>
Resulted in this output:
bool(true)
bool(true)
But I expected this output instead:
bool(true)
bool(false)
PHP Version
all supported version
Operating System
No response
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
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- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reproducing the example with password_hash(), password_verify(), PASSWORD_BCRYPT, and a null byte, then trace the PHP implementation and existing password verification tests. Done means a password with a null-byte suffix no longer verifies against the original bcrypt hash, while the unchanged password still verifies.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- c, php
- Domain
- authentication, security
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 48/100