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authorLinus Torvalds <torvalds@linux-foundation.org>2018-04-02 21:22:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-02 21:22:12 -0700
commit642e7fd23353e22290e3d51719fcb658dc252342 (patch)
tree93688d5ff15836d8e5b0e097748f7fabb13a303a /fs/namei.c
parent21035965f60b0502fc6537b232839389bb4ce664 (diff)
parentc9a211951c7c79cfb5de888d7d9550872868b086 (diff)
downloadlinux-stericsson-642e7fd23353e22290e3d51719fcb658dc252342.tar.gz
Merge branch 'syscalls-next' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux
Pull removal of in-kernel calls to syscalls from Dominik Brodowski: "System calls are interaction points between userspace and the kernel. Therefore, system call functions such as sys_xyzzy() or compat_sys_xyzzy() should only be called from userspace via the syscall table, but not from elsewhere in the kernel. At least on 64-bit x86, it will likely be a hard requirement from v4.17 onwards to not call system call functions in the kernel: It is better to use use a different calling convention for system calls there, where struct pt_regs is decoded on-the-fly in a syscall wrapper which then hands processing over to the actual syscall function. This means that only those parameters which are actually needed for a specific syscall are passed on during syscall entry, instead of filling in six CPU registers with random user space content all the time (which may cause serious trouble down the call chain). Those x86-specific patches will be pushed through the x86 tree in the near future. Moreover, rules on how data may be accessed may differ between kernel data and user data. This is another reason why calling sys_xyzzy() is generally a bad idea, and -- at most -- acceptable in arch-specific code. This patchset removes all in-kernel calls to syscall functions in the kernel with the exception of arch/. On top of this, it cleans up the three places where many syscalls are referenced or prototyped, namely kernel/sys_ni.c, include/linux/syscalls.h and include/linux/compat.h" * 'syscalls-next' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux: (109 commits) bpf: whitelist all syscalls for error injection kernel/sys_ni: remove {sys_,sys_compat} from cond_syscall definitions kernel/sys_ni: sort cond_syscall() entries syscalls/x86: auto-create compat_sys_*() prototypes syscalls: sort syscall prototypes in include/linux/compat.h net: remove compat_sys_*() prototypes from net/compat.h syscalls: sort syscall prototypes in include/linux/syscalls.h kexec: move sys_kexec_load() prototype to syscalls.h x86/sigreturn: use SYSCALL_DEFINE0 x86: fix sys_sigreturn() return type to be long, not unsigned long x86/ioport: add ksys_ioperm() helper; remove in-kernel calls to sys_ioperm() mm: add ksys_readahead() helper; remove in-kernel calls to sys_readahead() mm: add ksys_mmap_pgoff() helper; remove in-kernel calls to sys_mmap_pgoff() mm: add ksys_fadvise64_64() helper; remove in-kernel call to sys_fadvise64_64() fs: add ksys_fallocate() wrapper; remove in-kernel calls to sys_fallocate() fs: add ksys_p{read,write}64() helpers; remove in-kernel calls to syscalls fs: add ksys_truncate() wrapper; remove in-kernel calls to sys_truncate() fs: add ksys_sync_file_range helper(); remove in-kernel calls to syscall kernel: add ksys_setsid() helper; remove in-kernel call to sys_setsid() kernel: add ksys_unshare() helper; remove in-kernel calls to sys_unshare() ...
Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c61
1 files changed, 45 insertions, 16 deletions
diff --git a/fs/namei.c b/fs/namei.c
index cafa365eeb70..5c2b953c352d 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3729,8 +3729,8 @@ static int may_mknod(umode_t mode)
}
}
-SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
- unsigned, dev)
+long do_mknodat(int dfd, const char __user *filename, umode_t mode,
+ unsigned int dev)
{
struct dentry *dentry;
struct path path;
@@ -3773,9 +3773,15 @@ out:
return error;
}
+SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
+ unsigned int, dev)
+{
+ return do_mknodat(dfd, filename, mode, dev);
+}
+
SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, dev)
{
- return sys_mknodat(AT_FDCWD, filename, mode, dev);
+ return do_mknodat(AT_FDCWD, filename, mode, dev);
}
int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
@@ -3804,7 +3810,7 @@ int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
}
EXPORT_SYMBOL(vfs_mkdir);
-SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
+long do_mkdirat(int dfd, const char __user *pathname, umode_t mode)
{
struct dentry *dentry;
struct path path;
@@ -3829,9 +3835,14 @@ retry:
return error;
}
+SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
+{
+ return do_mkdirat(dfd, pathname, mode);
+}
+
SYSCALL_DEFINE2(mkdir, const char __user *, pathname, umode_t, mode)
{
- return sys_mkdirat(AT_FDCWD, pathname, mode);
+ return do_mkdirat(AT_FDCWD, pathname, mode);
}
int vfs_rmdir(struct inode *dir, struct dentry *dentry)
@@ -3873,7 +3884,7 @@ out:
}
EXPORT_SYMBOL(vfs_rmdir);
-static long do_rmdir(int dfd, const char __user *pathname)
+long do_rmdir(int dfd, const char __user *pathname)
{
int error = 0;
struct filename *name;
@@ -4109,8 +4120,8 @@ int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
}
EXPORT_SYMBOL(vfs_symlink);
-SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
- int, newdfd, const char __user *, newname)
+long do_symlinkat(const char __user *oldname, int newdfd,
+ const char __user *newname)
{
int error;
struct filename *from;
@@ -4140,9 +4151,15 @@ out_putname:
return error;
}
+SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
+ int, newdfd, const char __user *, newname)
+{
+ return do_symlinkat(oldname, newdfd, newname);
+}
+
SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname)
{
- return sys_symlinkat(oldname, AT_FDCWD, newname);
+ return do_symlinkat(oldname, AT_FDCWD, newname);
}
/**
@@ -4234,8 +4251,8 @@ EXPORT_SYMBOL(vfs_link);
* with linux 2.0, and to avoid hard-linking to directories
* and other special files. --ADM
*/
-SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
- int, newdfd, const char __user *, newname, int, flags)
+int do_linkat(int olddfd, const char __user *oldname, int newdfd,
+ const char __user *newname, int flags)
{
struct dentry *new_dentry;
struct path old_path, new_path;
@@ -4299,9 +4316,15 @@ out:
return error;
}
+SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
+ int, newdfd, const char __user *, newname, int, flags)
+{
+ return do_linkat(olddfd, oldname, newdfd, newname, flags);
+}
+
SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname)
{
- return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
+ return do_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
}
/**
@@ -4479,8 +4502,8 @@ out:
}
EXPORT_SYMBOL(vfs_rename);
-SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
- int, newdfd, const char __user *, newname, unsigned int, flags)
+static int do_renameat2(int olddfd, const char __user *oldname, int newdfd,
+ const char __user *newname, unsigned int flags)
{
struct dentry *old_dentry, *new_dentry;
struct dentry *trap;
@@ -4622,15 +4645,21 @@ exit:
return error;
}
+SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
+ int, newdfd, const char __user *, newname, unsigned int, flags)
+{
+ return do_renameat2(olddfd, oldname, newdfd, newname, flags);
+}
+
SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
int, newdfd, const char __user *, newname)
{
- return sys_renameat2(olddfd, oldname, newdfd, newname, 0);
+ return do_renameat2(olddfd, oldname, newdfd, newname, 0);
}
SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname)
{
- return sys_renameat2(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
+ return do_renameat2(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
}
int vfs_whiteout(struct inode *dir, struct dentry *dentry)