From: Pavel Machek
Sent: 18 August 2020 10:51
On Mon 2020-08-17 17:16:22, Greg Kroah-Hartman wrote:
From: Jim Cromie jim.cromie@gmail.com
[ Upstream commit f678ce8cc3cb2ad29df75d8824c74f36398ba871 ]
ddebug_describe_flags() currently fills a caller provided string buffer, after testing its size (also passed) in a BUG_ON. Fix this by replacing them with a known-big-enough string buffer wrapped in a struct, and passing that instead.
Also simplify ddebug_describe_flags() flags parameter from a struct to a member in that struct, and hoist the member deref up to the caller. This makes the function reusable (soon) where flags are unpacked.
Original code was correct, passing explicit size, this passes strange structure. BUG_ON can never trigger in the origianl code, so this is not a bugfix.
Embedding the char[] in a struct can be used to ensure that an incorrect size isn't passed.
But it still doesn't make it any more correct to not check the actual buffer won't be overrun.
In this case the code is still assuming that the buffer is large enough.
Odd code changes could (probably) still break it.
David
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