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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
parentfb041b598997d63c0f7d7305dfae70046bf66fe1 (diff)
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')
-rw-r--r--include/linux/compat.h16
-rw-r--r--include/linux/fs.h13
-rw-r--r--include/linux/uio.h12
3 files changed, 14 insertions, 27 deletions
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 790be5ffc12c..cebcaac68aec 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -91,6 +91,11 @@
static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
#endif /* COMPAT_SYSCALL_DEFINEx */
+struct compat_iovec {
+ compat_uptr_t iov_base;
+ compat_size_t iov_len;
+};
+
#ifdef CONFIG_COMPAT
#ifndef compat_user_stack_pointer
@@ -248,11 +253,6 @@ typedef struct compat_siginfo {
} _sifields;
} compat_siginfo_t;
-struct compat_iovec {
- compat_uptr_t iov_base;
- compat_size_t iov_len;
-};
-
struct compat_rlimit {
compat_ulong_t rlim_cur;
compat_ulong_t rlim_max;
@@ -451,12 +451,6 @@ extern long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
struct epoll_event; /* fortunately, this one is fixed-layout */
-extern ssize_t compat_rw_copy_check_uvector(int type,
- const struct compat_iovec __user *uvector,
- unsigned long nr_segs,
- unsigned long fast_segs, struct iovec *fast_pointer,
- struct iovec **ret_pointer);
-
extern void __user *compat_alloc_user_space(unsigned long len);
int compat_restore_altstack(const compat_stack_t __user *uss);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e019ea2f1347..b9fdac75ba06 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -179,14 +179,6 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
#define FMODE_BUF_RASYNC ((__force fmode_t)0x40000000)
/*
- * Flag for rw_copy_check_uvector and compat_rw_copy_check_uvector
- * that indicates that they should check the contents of the iovec are
- * valid, but not check the memory that the iovec elements
- * points too.
- */
-#define CHECK_IOVEC_ONLY -1
-
-/*
* Attribute flags. These should be or-ed together to figure out what
* has been changed!
*/
@@ -1887,11 +1879,6 @@ static inline int call_mmap(struct file *file, struct vm_area_struct *vma)
return file->f_op->mmap(file, vma);
}
-ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
- unsigned long nr_segs, unsigned long fast_segs,
- struct iovec *fast_pointer,
- struct iovec **ret_pointer);
-
extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
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;