diff --git a/fs/exec.c b/fs/exec.c index 1977c2a553aca711ba145d1670ea9a84fd45ea84..b06623a9347f4f206fb466c80574ec4bdd7d13fa 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -98,6 +98,12 @@ static inline void put_binfmt(struct linux_binfmt * fmt) module_put(fmt->module); } +bool path_noexec(const struct path *path) +{ + return (path->mnt->mnt_flags & MNT_NOEXEC) || + (path->mnt->mnt_sb->s_iflags & SB_I_NOEXEC); +} + #ifdef CONFIG_USELIB /* * Note that a shared library must be both readable and executable due to @@ -132,7 +138,7 @@ SYSCALL_DEFINE1(uselib, const char __user *, library) goto exit; error = -EACCES; - if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) + if (path_noexec(&file->f_path)) goto exit; fsnotify_open(file); @@ -777,7 +783,7 @@ static struct file *do_open_execat(int fd, struct filename *name, int flags) if (!S_ISREG(file_inode(file)->i_mode)) goto exit; - if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) + if (path_noexec(&file->f_path)) goto exit; err = deny_write_access(file); diff --git a/fs/open.c b/fs/open.c index e33dab287fa00a3d1d657e4b2d23c1f74529ae72..b6f1e96a7c0b331b3e5a5d9bb4c014c5c9edc54b 100644 --- a/fs/open.c +++ b/fs/open.c @@ -377,7 +377,7 @@ SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode) * with the "noexec" flag. */ res = -EACCES; - if (path.mnt->mnt_flags & MNT_NOEXEC) + if (path_noexec(&path)) goto out_path_release; } diff --git a/fs/proc/root.c b/fs/proc/root.c index 68feb0f70e6358f83f5a5281bf3c64d16cad2015..361ab4ee42fc3632232f4bc6eaef54a12f6b47e6 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -134,6 +134,8 @@ static struct dentry *proc_mount(struct file_system_type *fs_type, } sb->s_flags |= MS_ACTIVE; + /* User space would break if executables appear on proc */ + sb->s_iflags |= SB_I_NOEXEC; } return dget(sb->s_root); diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c index 1c6ac6fcee9fb15c869ef80fc5947ba9117d77ea..f3db82071cfbd5997bdb1393097e755ae730ea96 100644 --- a/fs/sysfs/mount.c +++ b/fs/sysfs/mount.c @@ -40,6 +40,10 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type, SYSFS_MAGIC, &new_sb, ns); if (IS_ERR(root) || !new_sb) kobj_ns_drop(KOBJ_NS_TYPE_NET, ns); + else if (new_sb) + /* Userspace would break if executables appear on sysfs */ + root->d_sb->s_iflags |= SB_I_NOEXEC; + return root; } diff --git a/include/linux/fs.h b/include/linux/fs.h index a0653e560c2679a2eea870035a55cd3282e47894..42912f8d286eb5c77fef0c39c550320e8ad1e736 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1244,6 +1244,7 @@ struct mm_struct; /* sb->s_iflags */ #define SB_I_CGROUPWB 0x00000001 /* cgroup-aware writeback enabled */ +#define SB_I_NOEXEC 0x00000002 /* Ignore executables on this fs */ /* Possible states of 'frozen' field */ enum { @@ -3030,4 +3031,6 @@ static inline bool dir_relax(struct inode *inode) return !IS_DEADDIR(inode); } +extern bool path_noexec(const struct path *path); + #endif /* _LINUX_FS_H */ diff --git a/kernel/sys.c b/kernel/sys.c index 259fda25eb6bac6dcbcfe788590a14ebb63e87f2..fa2f2f671a5cadb271367b13f8b119a21c8bf6b7 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1668,8 +1668,7 @@ static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd) * overall picture. */ err = -EACCES; - if (!S_ISREG(inode->i_mode) || - exe.file->f_path.mnt->mnt_flags & MNT_NOEXEC) + if (!S_ISREG(inode->i_mode) || path_noexec(&exe.file->f_path)) goto exit; err = inode_permission(inode, MAY_EXEC); diff --git a/mm/mmap.c b/mm/mmap.c index aa632ade2be797a9cc4f7a80e37884bc4e14745a..f126923ce683c6969a9ce2498bcd481d90d39b8e 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1268,7 +1268,7 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, * mounted, in which case we dont add PROT_EXEC.) */ if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) - if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC))) + if (!(file && path_noexec(&file->f_path))) prot |= PROT_EXEC; if (!(flags & MAP_FIXED)) @@ -1337,7 +1337,7 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, case MAP_PRIVATE: if (!(file->f_mode & FMODE_READ)) return -EACCES; - if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { + if (path_noexec(&file->f_path)) { if (vm_flags & VM_EXEC) return -EPERM; vm_flags &= ~VM_MAYEXEC; diff --git a/mm/nommu.c b/mm/nommu.c index 58ea3643b9e9968a723f498d7df55b34c51a179e..ce17abf087ff5917c5d51177ec4a331a240ed746 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1035,7 +1035,7 @@ static int validate_mmap_request(struct file *file, /* handle executable mappings and implied executable * mappings */ - if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { + if (path_noexec(&file->f_path)) { if (prot & PROT_EXEC) return -EPERM; } else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) { diff --git a/security/security.c b/security/security.c index 595fffab48b0a27077efa75ec9dd64e6983ae2d9..062f3c997fdc32a585c0ac02f72a108fee094f53 100644 --- a/security/security.c +++ b/security/security.c @@ -776,7 +776,7 @@ static inline unsigned long mmap_prot(struct file *file, unsigned long prot) * ditto if it's not on noexec mount, except that on !MMU we need * NOMMU_MAP_EXEC (== VM_MAYEXEC) in this case */ - if (!(file->f_path.mnt->mnt_flags & MNT_NOEXEC)) { + if (!path_noexec(&file->f_path)) { #ifndef CONFIG_MMU if (file->f_op->mmap_capabilities) { unsigned caps = file->f_op->mmap_capabilities(file);