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authorChristoph Hellwig <hch@lst.de>2020-09-25 07:51:40 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2020-10-03 07:01:56 +0300
commitbfdc59701d6d100c99c3b987bcffd1c204e393c8 (patch)
treea88294580eba288886916d767713789aa06507f2 /include/linux/compat.h
parentfb041b598997d63c0f7d7305dfae70046bf66fe1 (diff)
downloadlinux-bfdc59701d6d100c99c3b987bcffd1c204e393c8.tar.xz
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/compat.h')
-rw-r--r--include/linux/compat.h16
1 files changed, 5 insertions, 11 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);