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In commit96cfe2c0fd("mm/madvise: replace ptrace attach requirement for process_madvise") process_madvise() was updated to require the caller to possess the CAP_SYS_NICE capability to perform the operation, in addition to a check against PTRACE_MODE_READ performed by mm_access(). The mm_access() function explicitly checks to see if the address space of the process being referenced is the current one, in which case no check is performed. We, however, do not do this when checking the CAP_SYS_NICE capability. This means that we insist on the caller possessing this capability in order to perform madvise() operations on its own address space, which seems nonsensical. Simply add a check to allow for an invocation of this function with pidfd set to the current process without elevation. Link: https://lkml.kernel.org/r/20240913140628.77047-1-lorenzo.stoakes@oracle.com Fixes:96cfe2c0fd("mm/madvise: replace ptrace attach requirement for process_madvise") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: David Rientjes <rientjes@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.