Re: [patch] remove MNT_NOEXEC check for PROT_EXEC mmaps

[Stas Sergeev]

Hi.

Valdis.Kletnieks@xxxxxx wrote:
> > But why exactly? They do:
> > shm_open();
> > mmap(PROT_READ|PROT_WRITE|PROT_EXEC);
> > and mmap fails.
> > Where is the fault of an app here?
> Are you suggesting that it's not an app's fault/problem if it tries to
> open a writable file on a R/O filesystem?  Because it's essentially the
> same problem....
It is not really the same - the app is not trying to
create an "executable" file on a noexec filesystem.
PROT_EXEC never required the exec permission on a file
btw. The MAP_PRIVATE mmap roughly means a read of the
file into the memory, where the program can do anything
with its data, including an execution. Does the R/O
filesystem disallow PROT_WRITE for MAP_PRIVATE? Haven't
tried, but I hope it doesn't.

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