diff options
Diffstat (limited to 'fs/exec.c')
| -rw-r--r-- | fs/exec.c | 46 |
1 files changed, 26 insertions, 20 deletions
diff --git a/fs/exec.c b/fs/exec.c index 2f0acef8908e..f45859ad13ac 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -205,18 +205,10 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, /* * Avoid relying on expanding the stack down in GUP (which * does not work for STACK_GROWSUP anyway), and just do it - * by hand ahead of time. + * ahead of time. */ - if (write && pos < vma->vm_start) { - mmap_write_lock(mm); - ret = expand_downwards(vma, pos); - if (unlikely(ret < 0)) { - mmap_write_unlock(mm); - return NULL; - } - mmap_write_downgrade(mm); - } else - mmap_read_lock(mm); + if (!mmap_read_lock_maybe_expand(mm, vma, pos, write)) + return NULL; /* * We are doing an exec(). 'current' is the process @@ -763,8 +755,6 @@ int setup_arg_pages(struct linux_binprm *bprm, mm->arg_start = bprm->p; #endif - if (bprm->loader) - bprm->loader -= stack_shift; bprm->exec -= stack_shift; if (mmap_write_lock_killable(mm)) @@ -892,7 +882,8 @@ static struct file *do_open_execat(int fd, struct filename *name, int flags) .lookup_flags = LOOKUP_FOLLOW, }; - if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) + if ((flags & + ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH | AT_EXECVE_CHECK)) != 0) return ERR_PTR(-EINVAL); if (flags & AT_SYMLINK_NOFOLLOW) open_exec_flags.lookup_flags &= ~LOOKUP_FOLLOW; @@ -912,7 +903,7 @@ static struct file *do_open_execat(int fd, struct filename *name, int flags) path_noexec(&file->f_path)) return ERR_PTR(-EACCES); - err = deny_write_access(file); + err = exe_file_deny_write_access(file); if (err) return ERR_PTR(err); @@ -927,7 +918,7 @@ static struct file *do_open_execat(int fd, struct filename *name, int flags) * Returns ERR_PTR on failure or allocated struct file on success. * * As this is a wrapper for the internal do_open_execat(), callers - * must call allow_write_access() before fput() on release. Also see + * must call exe_file_allow_write_access() before fput() on release. Also see * do_close_execat(). */ struct file *open_exec(const char *name) @@ -1492,7 +1483,7 @@ static void do_close_execat(struct file *file) { if (!file) return; - allow_write_access(file); + exe_file_allow_write_access(file); fput(file); } @@ -1564,6 +1555,21 @@ static struct linux_binprm *alloc_bprm(int fd, struct filename *filename, int fl } bprm->interp = bprm->filename; + /* + * At this point, security_file_open() has already been called (with + * __FMODE_EXEC) and access control checks for AT_EXECVE_CHECK will + * stop just after the security_bprm_creds_for_exec() call in + * bprm_execve(). Indeed, the kernel should not try to parse the + * content of the file with exec_binprm() nor change the calling + * thread, which means that the following security functions will not + * be called: + * - security_bprm_check() + * - security_bprm_creds_from_file() + * - security_bprm_committing_creds() + * - security_bprm_committed_creds() + */ + bprm->is_check = !!(flags & AT_EXECVE_CHECK); + retval = bprm_mm_init(bprm); if (!retval) return bprm; @@ -1806,7 +1812,7 @@ static int exec_binprm(struct linux_binprm *bprm) bprm->file = bprm->interpreter; bprm->interpreter = NULL; - allow_write_access(exec); + exe_file_allow_write_access(exec); if (unlikely(bprm->have_execfd)) { if (bprm->executable) { fput(exec); @@ -1845,7 +1851,7 @@ static int bprm_execve(struct linux_binprm *bprm) /* Set the unchanging part of bprm->cred */ retval = security_bprm_creds_for_exec(bprm); - if (retval) + if (retval || bprm->is_check) goto out; retval = exec_binprm(bprm); @@ -2151,7 +2157,7 @@ static int proc_dointvec_minmax_coredump(const struct ctl_table *table, int writ return error; } -static struct ctl_table fs_exec_sysctls[] = { +static const struct ctl_table fs_exec_sysctls[] = { { .procname = "suid_dumpable", .data = &suid_dumpable, |