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authorChristoph Hellwig <hch@lst.de>2020-09-25 06:51:40 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2020-10-03 00:01:56 -0400
commitbfdc59701d6d100c99c3b987bcffd1c204e393c8 (patch)
treea88294580eba288886916d767713789aa06507f2 /include/linux/uio.h
parentfb041b598997d63c0f7d7305dfae70046bf66fe1 (diff)
downloadlinux-bfdc59701d6d100c99c3b987bcffd1c204e393c8.tar.gz
iov_iter: refactor rw_copy_check_uvector and import_iovec
Split rw_copy_check_uvector into two new helpers with more sensible calling conventions: - iovec_from_user copies a iovec from userspace either into the provided stack buffer if it fits, or allocates a new buffer for it. Returns the actually used iovec. It also verifies that iov_len does fit a signed type, and handles compat iovecs if the compat flag is set. - __import_iovec consolidates the native and compat versions of import_iovec. It calls iovec_from_user, then validates each iovec actually points to user addresses, and ensures the total length doesn't overflow. This has two major implications: - the access_process_vm case loses the total lenght checking, which wasn't required anyway, given that each call receives two iovecs for the local and remote side of the operation, and it verifies the total length on the local side already. - instead of a single loop there now are two loops over the iovecs. Given that the iovecs are cache hot this doesn't make a major difference Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include/linux/uio.h')
-rw-r--r--include/linux/uio.h12
1 files changed, 9 insertions, 3 deletions
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 3835a8a8e9ea..92c11fe41c62 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -266,9 +266,15 @@ bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, struct
size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp,
struct iov_iter *i);
-ssize_t import_iovec(int type, const struct iovec __user * uvector,
- unsigned nr_segs, unsigned fast_segs,
- struct iovec **iov, struct iov_iter *i);
+struct iovec *iovec_from_user(const struct iovec __user *uvector,
+ unsigned long nr_segs, unsigned long fast_segs,
+ struct iovec *fast_iov, bool compat);
+ssize_t import_iovec(int type, const struct iovec __user *uvec,
+ unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
+ struct iov_iter *i);
+ssize_t __import_iovec(int type, const struct iovec __user *uvec,
+ unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
+ struct iov_iter *i, bool compat);
#ifdef CONFIG_COMPAT
struct compat_iovec;