diff options
| -rw-r--r-- | fs/binfmt_em86.c | 4 | ||||
| -rw-r--r-- | fs/binfmt_misc.c | 4 | ||||
| -rw-r--r-- | fs/binfmt_script.c | 10 | ||||
| -rw-r--r-- | fs/exec.c | 113 | ||||
| -rw-r--r-- | fs/namei.c | 2 | ||||
| -rw-r--r-- | include/linux/binfmts.h | 4 | ||||
| -rw-r--r-- | include/linux/compat.h | 3 | ||||
| -rw-r--r-- | include/linux/fs.h | 1 | ||||
| -rw-r--r-- | include/linux/sched.h | 4 | ||||
| -rw-r--r-- | include/linux/syscalls.h | 5 | ||||
| -rw-r--r-- | include/uapi/asm-generic/unistd.h | 4 | ||||
| -rw-r--r-- | kernel/sys_ni.c | 3 | ||||
| -rw-r--r-- | lib/audit.c | 3 |
13 files changed, 145 insertions, 15 deletions
diff --git a/fs/binfmt_em86.c b/fs/binfmt_em86.c index f37b08c..4905385 100644 --- a/fs/binfmt_em86.c +++ b/fs/binfmt_em86.c @@ -42,6 +42,10 @@ static int load_em86(struct linux_binprm *bprm) return -ENOEXEC; } + /* Need to be able to load the file after exec */ + if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) + return -ENOENT; + allow_write_access(bprm->file); fput(bprm->file); bprm->file = NULL; diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c index 70789e1..c04ef1d 100644 --- a/fs/binfmt_misc.c +++ b/fs/binfmt_misc.c @@ -144,6 +144,10 @@ static int load_misc_binary(struct linux_binprm *bprm) if (!fmt) goto ret; + /* Need to be able to load the file after exec */ + if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) + return -ENOENT; + if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) { retval = remove_arg_zero(bprm); if (retval) diff --git a/fs/binfmt_script.c b/fs/binfmt_script.c index 5027a3e..afdf4e3 100644 --- a/fs/binfmt_script.c +++ b/fs/binfmt_script.c @@ -24,6 +24,16 @@ static int load_script(struct linux_binprm *bprm) if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!')) return -ENOEXEC; + + /* + * If the script filename will be inaccessible after exec, typically + * because it is a "/dev/fd/<fd>/.." path against an O_CLOEXEC fd, give + * up now (on the assumption that the interpreter will want to load + * this file). + */ + if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) + return -ENOENT; + /* * This section does the #! interpretation. * Sorta complicated, but hopefully it will work. -TYT @@ -748,18 +748,25 @@ EXPORT_SYMBOL(setup_arg_pages); #endif /* CONFIG_MMU */ -static struct file *do_open_exec(struct filename *name) +static struct file *do_open_execat(int fd, struct filename *name, int flags) { struct file *file; int err; - static const struct open_flags open_exec_flags = { + struct open_flags open_exec_flags = { .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, .acc_mode = MAY_EXEC | MAY_OPEN, .intent = LOOKUP_OPEN, .lookup_flags = LOOKUP_FOLLOW, }; - file = do_filp_open(AT_FDCWD, name, &open_exec_flags); + if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) + return ERR_PTR(-EINVAL); + if (flags & AT_SYMLINK_NOFOLLOW) + open_exec_flags.lookup_flags &= ~LOOKUP_FOLLOW; + if (flags & AT_EMPTY_PATH) + open_exec_flags.lookup_flags |= LOOKUP_EMPTY; + + file = do_filp_open(fd, name, &open_exec_flags); if (IS_ERR(file)) goto out; @@ -770,12 +777,13 @@ static struct file *do_open_exec(struct filename *name) if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) goto exit; - fsnotify_open(file); - err = deny_write_access(file); if (err) goto exit; + if (name->name[0] != '\0') + fsnotify_open(file); + out: return file; @@ -787,7 +795,7 @@ exit: struct file *open_exec(const char *name) { struct filename tmp = { .name = name }; - return do_open_exec(&tmp); + return do_open_execat(AT_FDCWD, &tmp, 0); } EXPORT_SYMBOL(open_exec); @@ -1428,10 +1436,12 @@ static int exec_binprm(struct linux_binprm *bprm) /* * sys_execve() executes a new program. */ -static int do_execve_common(struct filename *filename, - struct user_arg_ptr argv, - struct user_arg_ptr envp) +static int do_execveat_common(int fd, struct filename *filename, + struct user_arg_ptr argv, + struct user_arg_ptr envp, + int flags) { + char *pathbuf = NULL; struct linux_binprm *bprm; struct file *file; struct files_struct *displaced; @@ -1472,7 +1482,7 @@ static int do_execve_common(struct filename *filename, check_unsafe_exec(bprm); current->in_execve = 1; - file = do_open_exec(filename); + file = do_open_execat(fd, filename, flags); retval = PTR_ERR(file); if (IS_ERR(file)) goto out_unmark; @@ -1480,7 +1490,28 @@ static int do_execve_common(struct filename *filename, sched_exec(); bprm->file = file; - bprm->filename = bprm->interp = filename->name; + if (fd == AT_FDCWD || filename->name[0] == '/') { + bprm->filename = filename->name; + } else { + if (filename->name[0] == '\0') + pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d", fd); + else + pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d/%s", + fd, filename->name); + if (!pathbuf) { + retval = -ENOMEM; + goto out_unmark; + } + /* + * Record that a name derived from an O_CLOEXEC fd will be + * inaccessible after exec. Relies on having exclusive access to + * current->files (due to unshare_files above). + */ + if (close_on_exec(fd, rcu_dereference_raw(current->files->fdt))) + bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE; + bprm->filename = pathbuf; + } + bprm->interp = bprm->filename; retval = bprm_mm_init(bprm); if (retval) @@ -1521,6 +1552,7 @@ static int do_execve_common(struct filename *filename, acct_update_integrals(current); task_numa_free(current); free_bprm(bprm); + kfree(pathbuf); putname(filename); if (displaced) put_files_struct(displaced); @@ -1538,6 +1570,7 @@ out_unmark: out_free: free_bprm(bprm); + kfree(pathbuf); out_files: if (displaced) @@ -1553,7 +1586,18 @@ int do_execve(struct filename *filename, { struct user_arg_ptr argv = { .ptr.native = __argv }; struct user_arg_ptr envp = { .ptr.native = __envp }; - return do_execve_common(filename, argv, envp); + return do_execveat_common(AT_FDCWD, filename, argv, envp, 0); +} + +int do_execveat(int fd, struct filename *filename, + const char __user *const __user *__argv, + const char __user *const __user *__envp, + int flags) +{ + struct user_arg_ptr argv = { .ptr.native = __argv }; + struct user_arg_ptr envp = { .ptr.native = __envp }; + + return do_execveat_common(fd, filename, argv, envp, flags); } #ifdef CONFIG_COMPAT @@ -1569,7 +1613,23 @@ static int compat_do_execve(struct filename *filename, .is_compat = true, .ptr.compat = __envp, }; - return do_execve_common(filename, argv, envp); + return do_execveat_common(AT_FDCWD, filename, argv, envp, 0); +} + +static int compat_do_execveat(int fd, struct filename *filename, + const compat_uptr_t __user *__argv, + const compat_uptr_t __user *__envp, + int flags) +{ + struct user_arg_ptr argv = { + .is_compat = true, + .ptr.compat = __argv, + }; + struct user_arg_ptr envp = { + .is_compat = true, + .ptr.compat = __envp, + }; + return do_execveat_common(fd, filename, argv, envp, flags); } #endif @@ -1609,6 +1669,20 @@ SYSCALL_DEFINE3(execve, { return do_execve(getname(filename), argv, envp); } + +SYSCALL_DEFINE5(execveat, + int, fd, const char __user *, filename, + const char __user *const __user *, argv, + const char __user *const __user *, envp, + int, flags) +{ + int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; + + return do_execveat(fd, + getname_flags(filename, lookup_flags, NULL), + argv, envp, flags); +} + #ifdef CONFIG_COMPAT COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename, const compat_uptr_t __user *, argv, @@ -1616,4 +1690,17 @@ COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename, { return compat_do_execve(getname(filename), argv, envp); } + +COMPAT_SYSCALL_DEFINE5(execveat, int, fd, + const char __user *, filename, + const compat_uptr_t __user *, argv, + const compat_uptr_t __user *, envp, + int, flags) +{ + int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; + + return compat_do_execveat(fd, + getname_flags(filename, lookup_flags, NULL), + argv, envp, flags); +} #endif @@ -130,7 +130,7 @@ void final_putname(struct filename *name) #define EMBEDDED_NAME_MAX (PATH_MAX - sizeof(struct filename)) -static struct filename * +struct filename * getname_flags(const char __user *filename, int flags, int *empty) { struct filename *result, *err; diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h index 61f29e5..576e463 100644 --- a/include/linux/binfmts.h +++ b/include/linux/binfmts.h @@ -53,6 +53,10 @@ struct linux_binprm { #define BINPRM_FLAGS_EXECFD_BIT 1 #define BINPRM_FLAGS_EXECFD (1 << BINPRM_FLAGS_EXECFD_BIT) +/* filename of the binary will be inaccessible after exec */ +#define BINPRM_FLAGS_PATH_INACCESSIBLE_BIT 2 +#define BINPRM_FLAGS_PATH_INACCESSIBLE (1 << BINPRM_FLAGS_PATH_INACCESSIBLE_BIT) + /* Function parameter for binfmt->coredump */ struct coredump_params { const siginfo_t *siginfo; diff --git a/include/linux/compat.h b/include/linux/compat.h index e649426..7450ca2 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -357,6 +357,9 @@ asmlinkage long compat_sys_lseek(unsigned int, compat_off_t, unsigned int); asmlinkage long compat_sys_execve(const char __user *filename, const compat_uptr_t __user *argv, const compat_uptr_t __user *envp); +asmlinkage long compat_sys_execveat(int dfd, const char __user *filename, + const compat_uptr_t __user *argv, + const compat_uptr_t __user *envp, int flags); asmlinkage long compat_sys_select(int n, compat_ulong_t __user *inp, compat_ulong_t __user *outp, compat_ulong_t __user *exp, diff --git a/include/linux/fs.h b/include/linux/fs.h index 1d1838d..4193a0bd 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2096,6 +2096,7 @@ extern int vfs_open(const struct path *, struct file *, const struct cred *); extern struct file * dentry_open(const struct path *, int, const struct cred *); extern int filp_close(struct file *, fl_owner_t id); +extern struct filename *getname_flags(const char __user *, int, int *); extern struct filename *getname(const char __user *); extern struct filename *getname_kernel(const char *); diff --git a/include/linux/sched.h b/include/linux/sched.h index 4cfdbcf..8db31ef 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2485,6 +2485,10 @@ extern void do_group_exit(int); extern int do_execve(struct filename *, const char __user * const __user *, const char __user * const __user *); +extern int do_execveat(int, struct filename *, + const char __user * const __user *, + const char __user * const __user *, + int); extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *); struct task_struct *fork_idle(int); extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags); diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index c9afdc7..85893d7 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -877,4 +877,9 @@ asmlinkage long sys_seccomp(unsigned int op, unsigned int flags, asmlinkage long sys_getrandom(char __user *buf, size_t count, unsigned int flags); asmlinkage long sys_bpf(int cmd, union bpf_attr *attr, unsigned int size); + +asmlinkage long sys_execveat(int dfd, const char __user *filename, + const char __user *const __user *argv, + const char __user *const __user *envp, int flags); + #endif diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h index 22749c1..e016bd9 100644 --- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h @@ -707,9 +707,11 @@ __SYSCALL(__NR_getrandom, sys_getrandom) __SYSCALL(__NR_memfd_create, sys_memfd_create) #define __NR_bpf 280 __SYSCALL(__NR_bpf, sys_bpf) +#define __NR_execveat 281 +__SC_COMP(__NR_execveat, sys_execveat, compat_sys_execveat) #undef __NR_syscalls -#define __NR_syscalls 281 +#define __NR_syscalls 282 /* * All syscalls below here should go away really, diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index 61eea02..5adcb0a 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -226,3 +226,6 @@ cond_syscall(sys_seccomp); /* access BPF programs and maps */ cond_syscall(sys_bpf); + +/* execveat */ +cond_syscall(sys_execveat); diff --git a/lib/audit.c b/lib/audit.c index 1d726a2..b8fb5ee 100644 --- a/lib/audit.c +++ b/lib/audit.c @@ -54,6 +54,9 @@ int audit_classify_syscall(int abi, unsigned syscall) case __NR_socketcall: return 4; #endif +#ifdef __NR_execveat + case __NR_execveat: +#endif case __NR_execve: return 5; default: |
