diff options
| -rw-r--r-- | include/linux/compat.h | 16 | ||||
| -rw-r--r-- | include/linux/fs.h | 13 | ||||
| -rw-r--r-- | include/linux/uio.h | 12 | ||||
| -rw-r--r-- | lib/iov_iter.c | 300 | ||||
| -rw-r--r-- | mm/process_vm_access.c | 34 |
5 files changed, 143 insertions, 232 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; diff --git a/lib/iov_iter.c b/lib/iov_iter.c index ccea9db3f72b..e6cb51da3424 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -7,6 +7,7 @@ #include <linux/slab.h> #include <linux/vmalloc.h> #include <linux/splice.h> +#include <linux/compat.h> #include <net/checksum.h> #include <linux/scatterlist.h> #include <linux/instrumented.h> @@ -1650,107 +1651,133 @@ const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) } EXPORT_SYMBOL(dup_iter); -/** - * rw_copy_check_uvector() - Copy an array of &struct iovec from userspace - * into the kernel and check that it is valid. - * - * @type: One of %CHECK_IOVEC_ONLY, %READ, or %WRITE. - * @uvector: Pointer to the userspace array. - * @nr_segs: Number of elements in userspace array. - * @fast_segs: Number of elements in @fast_pointer. - * @fast_pointer: Pointer to (usually small on-stack) kernel array. - * @ret_pointer: (output parameter) Pointer to a variable that will point to - * either @fast_pointer, a newly allocated kernel array, or NULL, - * depending on which array was used. - * - * This function copies an array of &struct iovec of @nr_segs from - * userspace into the kernel and checks that each element is valid (e.g. - * it does not point to a kernel address or cause overflow by being too - * large, etc.). - * - * As an optimization, the caller may provide a pointer to a small - * on-stack array in @fast_pointer, typically %UIO_FASTIOV elements long - * (the size of this array, or 0 if unused, should be given in @fast_segs). - * - * @ret_pointer will always point to the array that was used, so the - * caller must take care not to call kfree() on it e.g. in case the - * @fast_pointer array was used and it was allocated on the stack. - * - * Return: The total number of bytes covered by the iovec array on success - * or a negative error code on error. - */ -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) +static int copy_compat_iovec_from_user(struct iovec *iov, + const struct iovec __user *uvec, unsigned long nr_segs) +{ + const struct compat_iovec __user *uiov = + (const struct compat_iovec __user *)uvec; + int ret = -EFAULT, i; + + if (!user_access_begin(uvec, nr_segs * sizeof(*uvec))) + return -EFAULT; + + for (i = 0; i < nr_segs; i++) { + compat_uptr_t buf; + compat_ssize_t len; + + unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); + unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); + + /* check for compat_size_t not fitting in compat_ssize_t .. */ + if (len < 0) { + ret = -EINVAL; + goto uaccess_end; + } + iov[i].iov_base = compat_ptr(buf); + iov[i].iov_len = len; + } + + ret = 0; +uaccess_end: + user_access_end(); + return ret; +} + +static int copy_iovec_from_user(struct iovec *iov, + const struct iovec __user *uvec, unsigned long nr_segs) { unsigned long seg; - ssize_t ret; - struct iovec *iov = fast_pointer; - /* - * SuS says "The readv() function *may* fail if the iovcnt argument - * was less than or equal to 0, or greater than {IOV_MAX}. Linux has - * traditionally returned zero for zero segments, so... - */ - if (nr_segs == 0) { - ret = 0; - goto out; + if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) + return -EFAULT; + for (seg = 0; seg < nr_segs; seg++) { + if ((ssize_t)iov[seg].iov_len < 0) + return -EINVAL; } + return 0; +} + +struct iovec *iovec_from_user(const struct iovec __user *uvec, + unsigned long nr_segs, unsigned long fast_segs, + struct iovec *fast_iov, bool compat) +{ + struct iovec *iov = fast_iov; + int ret; + /* - * First get the "struct iovec" from user memory and - * verify all the pointers + * SuS says "The readv() function *may* fail if the iovcnt argument was + * less than or equal to 0, or greater than {IOV_MAX}. Linux has + * traditionally returned zero for zero segments, so... */ - if (nr_segs > UIO_MAXIOV) { - ret = -EINVAL; - goto out; - } + if (nr_segs == 0) + return iov; + if (nr_segs > UIO_MAXIOV) + return ERR_PTR(-EINVAL); if (nr_segs > fast_segs) { iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); - if (iov == NULL) { - ret = -ENOMEM; - goto out; - } + if (!iov) + return ERR_PTR(-ENOMEM); } - if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) { - ret = -EFAULT; - goto out; + + if (compat) + ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); + else + ret = copy_iovec_from_user(iov, uvec, nr_segs); + if (ret) { + if (iov != fast_iov) + kfree(iov); + return ERR_PTR(ret); + } + + return iov; +} + +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) +{ + ssize_t total_len = 0; + unsigned long seg; + struct iovec *iov; + + iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); + if (IS_ERR(iov)) { + *iovp = NULL; + return PTR_ERR(iov); } /* - * According to the Single Unix Specification we should return EINVAL - * if an element length is < 0 when cast to ssize_t or if the - * total length would overflow the ssize_t return value of the - * system call. + * According to the Single Unix Specification we should return EINVAL if + * an element length is < 0 when cast to ssize_t or if the total length + * would overflow the ssize_t return value of the system call. * * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the * overflow case. */ - ret = 0; for (seg = 0; seg < nr_segs; seg++) { - void __user *buf = iov[seg].iov_base; ssize_t len = (ssize_t)iov[seg].iov_len; - /* see if we we're about to use an invalid len or if - * it's about to overflow ssize_t */ - if (len < 0) { - ret = -EINVAL; - goto out; + if (!access_ok(iov[seg].iov_base, len)) { + if (iov != *iovp) + kfree(iov); + *iovp = NULL; + return -EFAULT; } - if (type >= 0 - && unlikely(!access_ok(buf, len))) { - ret = -EFAULT; - goto out; - } - if (len > MAX_RW_COUNT - ret) { - len = MAX_RW_COUNT - ret; + + if (len > MAX_RW_COUNT - total_len) { + len = MAX_RW_COUNT - total_len; iov[seg].iov_len = len; } - ret += len; + total_len += len; } -out: - *ret_pointer = iov; - return ret; + + iov_iter_init(i, type, iov, nr_segs, total_len); + if (iov == *iovp) + *iovp = NULL; + else + *iovp = iov; + return total_len; } /** @@ -1759,10 +1786,10 @@ out: * &struct iov_iter iterator to access it. * * @type: One of %READ or %WRITE. - * @uvector: Pointer to the userspace array. + * @uvec: Pointer to the userspace array. * @nr_segs: Number of elements in userspace array. * @fast_segs: Number of elements in @iov. - * @iov: (input and output parameter) Pointer to pointer to (usually small + * @iovp: (input and output parameter) Pointer to pointer to (usually small * on-stack) kernel array. * @i: Pointer to iterator that will be initialized on success. * @@ -1775,120 +1802,21 @@ out: * * Return: Negative error code on error, bytes imported on success */ -ssize_t import_iovec(int type, const struct iovec __user * uvector, +ssize_t import_iovec(int type, const struct iovec __user *uvec, unsigned nr_segs, unsigned fast_segs, - struct iovec **iov, struct iov_iter *i) + struct iovec **iovp, struct iov_iter *i) { - ssize_t n; - struct iovec *p; - n = rw_copy_check_uvector(type, uvector, nr_segs, fast_segs, - *iov, &p); - if (n < 0) { - if (p != *iov) - kfree(p); - *iov = NULL; - return n; - } - iov_iter_init(i, type, p, nr_segs, n); - *iov = p == *iov ? NULL : p; - return n; + return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, false); } EXPORT_SYMBOL(import_iovec); #ifdef CONFIG_COMPAT -#include <linux/compat.h> - -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) -{ - compat_ssize_t tot_len; - struct iovec *iov = *ret_pointer = fast_pointer; - ssize_t ret = 0; - int seg; - - /* - * SuS says "The readv() function *may* fail if the iovcnt argument - * was less than or equal to 0, or greater than {IOV_MAX}. Linux has - * traditionally returned zero for zero segments, so... - */ - if (nr_segs == 0) - goto out; - - ret = -EINVAL; - if (nr_segs > UIO_MAXIOV) - goto out; - if (nr_segs > fast_segs) { - ret = -ENOMEM; - iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); - if (iov == NULL) - goto out; - } - *ret_pointer = iov; - - ret = -EFAULT; - if (!access_ok(uvector, nr_segs*sizeof(*uvector))) - goto out; - - /* - * Single unix specification: - * We should -EINVAL if an element length is not >= 0 and fitting an - * ssize_t. - * - * In Linux, the total length is limited to MAX_RW_COUNT, there is - * no overflow possibility. - */ - tot_len = 0; - ret = -EINVAL; - for (seg = 0; seg < nr_segs; seg++) { - compat_uptr_t buf; - compat_ssize_t len; - - if (__get_user(len, &uvector->iov_len) || - __get_user(buf, &uvector->iov_base)) { - ret = -EFAULT; - goto out; - } - if (len < 0) /* size_t not fitting in compat_ssize_t .. */ - goto out; - if (type >= 0 && - !access_ok(compat_ptr(buf), len)) { - ret = -EFAULT; - goto out; - } - if (len > MAX_RW_COUNT - tot_len) - len = MAX_RW_COUNT - tot_len; - tot_len += len; - iov->iov_base = compat_ptr(buf); - iov->iov_len = (compat_size_t) len; - uvector++; - iov++; - } - ret = tot_len; - -out: - return ret; -} - -ssize_t compat_import_iovec(int type, - const struct compat_iovec __user * uvector, - unsigned nr_segs, unsigned fast_segs, - struct iovec **iov, struct iov_iter *i) +ssize_t compat_import_iovec(int type, const struct compat_iovec __user *uvec, + unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, + struct iov_iter *i) { - ssize_t n; - struct iovec *p; - n = compat_rw_copy_check_uvector(type, uvector, nr_segs, fast_segs, - *iov, &p); - if (n < 0) { - if (p != *iov) - kfree(p); - *iov = NULL; - return n; - } - iov_iter_init(i, type, p, nr_segs, n); - *iov = p == *iov ? NULL : p; - return n; + return __import_iovec(type, (const struct iovec __user *)uvec, nr_segs, + fast_segs, iovp, i, true); } EXPORT_SYMBOL(compat_import_iovec); #endif diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c index 29c052099aff..5e728c20c2be 100644 --- a/mm/process_vm_access.c +++ b/mm/process_vm_access.c @@ -276,20 +276,17 @@ static ssize_t process_vm_rw(pid_t pid, if (rc < 0) return rc; if (!iov_iter_count(&iter)) - goto free_iovecs; - - rc = rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt, UIO_FASTIOV, - iovstack_r, &iov_r); - if (rc <= 0) - goto free_iovecs; - + goto free_iov_l; + iov_r = iovec_from_user(rvec, riovcnt, UIO_FASTIOV, iovstack_r, false); + if (IS_ERR(iov_r)) { + rc = PTR_ERR(iov_r); + goto free_iov_l; + } rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write); - -free_iovecs: if (iov_r != iovstack_r) kfree(iov_r); +free_iov_l: kfree(iov_l); - return rc; } @@ -333,18 +330,17 @@ compat_process_vm_rw(compat_pid_t pid, if (rc < 0) return rc; if (!iov_iter_count(&iter)) - goto free_iovecs; - rc = compat_rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt, - UIO_FASTIOV, iovstack_r, - &iov_r); - if (rc <= 0) - goto free_iovecs; - + goto free_iov_l; + iov_r = iovec_from_user((const struct iovec __user *)rvec, riovcnt, + UIO_FASTIOV, iovstack_r, true); + if (IS_ERR(iov_r)) { + rc = PTR_ERR(iov_r); + goto free_iov_l; + } rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write); - -free_iovecs: if (iov_r != iovstack_r) kfree(iov_r); +free_iov_l: kfree(iov_l); return rc; } |