8aec0f5d41
Looking at mm/process_vm_access.c:process_vm_rw() and comparing it to compat_process_vm_rw() shows that the compatibility code requires an explicit "access_ok()" check before calling compat_rw_copy_check_uvector(). The same difference seems to appear when we compare fs/read_write.c:do_readv_writev() to fs/compat.c:compat_do_readv_writev(). This subtle difference between the compat and non-compat requirements should probably be debated, as it seems to be error-prone. In fact, there are two others sites that use this function in the Linux kernel, and they both seem to get it wrong: Now shifting our attention to fs/aio.c, we see that aio_setup_iocb() also ends up calling compat_rw_copy_check_uvector() through aio_setup_vectored_rw(). Unfortunately, the access_ok() check appears to be missing. Same situation for security/keys/compat.c:compat_keyctl_instantiate_key_iov(). I propose that we add the access_ok() check directly into compat_rw_copy_check_uvector(), so callers don't have to worry about it, and it therefore makes the compat call code similar to its non-compat counterpart. Place the access_ok() check in the same location where copy_from_user() can trigger a -EFAULT error in the non-compat code, so the ABI behaviors are alike on both compat and non-compat. While we are here, fix compat_do_readv_writev() so it checks for compat_rw_copy_check_uvector() negative return values. And also, fix a memory leak in compat_keyctl_instantiate_key_iov() error handling. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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.. | ||
backing-dev.c | ||
balloon_compaction.c | ||
bootmem.c | ||
bounce.c | ||
cleancache.c | ||
compaction.c | ||
debug-pagealloc.c | ||
dmapool.c | ||
fadvise.c | ||
failslab.c | ||
filemap.c | ||
filemap_xip.c | ||
fremap.c | ||
frontswap.c | ||
highmem.c | ||
huge_memory.c | ||
hugetlb.c | ||
hugetlb_cgroup.c | ||
hwpoison-inject.c | ||
init-mm.c | ||
internal.h | ||
interval_tree.c | ||
Kconfig | ||
Kconfig.debug | ||
kmemcheck.c | ||
kmemleak-test.c | ||
kmemleak.c | ||
ksm.c | ||
maccess.c | ||
madvise.c | ||
Makefile | ||
memblock.c | ||
memcontrol.c | ||
memory-failure.c | ||
memory.c | ||
memory_hotplug.c | ||
mempolicy.c | ||
mempool.c | ||
migrate.c | ||
mincore.c | ||
mlock.c | ||
mm_init.c | ||
mmap.c | ||
mmu_context.c | ||
mmu_notifier.c | ||
mmzone.c | ||
mprotect.c | ||
mremap.c | ||
msync.c | ||
nobootmem.c | ||
nommu.c | ||
oom_kill.c | ||
page-writeback.c | ||
page_alloc.c | ||
page_cgroup.c | ||
page_io.c | ||
page_isolation.c | ||
pagewalk.c | ||
percpu-km.c | ||
percpu-vm.c | ||
percpu.c | ||
pgtable-generic.c | ||
process_vm_access.c | ||
quicklist.c | ||
readahead.c | ||
rmap.c | ||
shmem.c | ||
slab.c | ||
slab.h | ||
slab_common.c | ||
slob.c | ||
slub.c | ||
sparse-vmemmap.c | ||
sparse.c | ||
swap.c | ||
swap_state.c | ||
swapfile.c | ||
truncate.c | ||
util.c | ||
vmalloc.c | ||
vmscan.c | ||
vmstat.c |