X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=fs%2Fexec.c;h=8cf76e2a0b83e2777f01f51a0a89efd68e4b7127;hb=18c3962f90eabccce864af692bd7cb30439bdc2b;hp=eadbf5069c388ab5431a271a39e5814cbb50b0d0;hpb=00198dab3b825ab264424a052beea5acb859754f;p=mirror_ubuntu-zesty-kernel.git

diff --git a/fs/exec.c b/fs/exec.c
index eadbf5069c38..8cf76e2a0b83 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -58,7 +58,9 @@
 #include <linux/compat.h>
 #include <linux/vmalloc.h>
 
-#include <asm/uaccess.h>
+#include <trace/events/fs.h>
+
+#include <linux/uaccess.h>
 #include <asm/mmu_context.h>
 #include <asm/tlb.h>
 
@@ -104,6 +106,14 @@ bool path_noexec(const struct path *path)
 	return (path->mnt->mnt_flags & MNT_NOEXEC) ||
 	       (path->mnt->mnt_sb->s_iflags & SB_I_NOEXEC);
 }
+EXPORT_SYMBOL_GPL(path_noexec);
+
+bool path_nosuid(const struct path *path)
+{
+	return !mnt_may_suid(path->mnt) ||
+	       (path->mnt->mnt_sb->s_iflags & SB_I_NOSUID);
+}
+EXPORT_SYMBOL(path_nosuid);
 
 #ifdef CONFIG_USELIB
 /*
@@ -215,8 +225,26 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
 
 	if (write) {
 		unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start;
+		unsigned long ptr_size;
 		struct rlimit *rlim;
 
+		/*
+		 * Since the stack will hold pointers to the strings, we
+		 * must account for them as well.
+		 *
+		 * The size calculation is the entire vma while each arg page is
+		 * built, so each time we get here it's calculating how far it
+		 * is currently (rather than each call being just the newly
+		 * added size from the arg page).  As a result, we need to
+		 * always add the entire size of the pointers, so that on the
+		 * last call to get_arg_page() we'll actually have the entire
+		 * correct size.
+		 */
+		ptr_size = (bprm->argc + bprm->envc) * sizeof(void *);
+		if (ptr_size > ULONG_MAX - size)
+			goto fail;
+		size += ptr_size;
+
 		acct_arg_size(bprm, size / PAGE_SIZE);
 
 		/*
@@ -234,13 +262,15 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
 		 *    to work from.
 		 */
 		rlim = current->signal->rlim;
-		if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) {
-			put_page(page);
-			return NULL;
-		}
+		if (size > READ_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4)
+			goto fail;
 	}
 
 	return page;
+
+fail:
+	put_page(page);
+	return NULL;
 }
 
 static void put_arg_page(struct page *page)
@@ -838,6 +868,8 @@ static struct file *do_open_execat(int fd, struct filename *name, int flags)
 	if (name->name[0] != '\0')
 		fsnotify_open(file);
 
+	trace_open_exec(name->name);
+
 out:
 	return file;
 
@@ -1425,6 +1457,7 @@ static void check_unsafe_exec(struct linux_binprm *bprm)
 {
 	struct task_struct *p = current, *t;
 	unsigned n_fs;
+	bool fs_recheck;
 
 	if (p->ptrace) {
 		if (ptracer_capable(p, current_user_ns()))
@@ -1440,6 +1473,8 @@ static void check_unsafe_exec(struct linux_binprm *bprm)
 	if (task_no_new_privs(current))
 		bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS;
 
+recheck:
+	fs_recheck = false;
 	t = p;
 	n_fs = 1;
 	spin_lock(&p->fs->lock);
@@ -1447,12 +1482,18 @@ static void check_unsafe_exec(struct linux_binprm *bprm)
 	while_each_thread(p, t) {
 		if (t->fs == p->fs)
 			n_fs++;
+		if (t->flags & (PF_EXITING | PF_FORKNOEXEC))
+			fs_recheck  = true;
 	}
 	rcu_read_unlock();
 
-	if (p->fs->users > n_fs)
+	if (p->fs->users > n_fs) {
+		if (fs_recheck) {
+			spin_unlock(&p->fs->lock);
+			goto recheck;
+		}
 		bprm->unsafe |= LSM_UNSAFE_SHARE;
-	else
+	} else
 		p->fs->in_exec = 1;
 	spin_unlock(&p->fs->lock);
 }
@@ -1473,7 +1514,7 @@ static void bprm_fill_uid(struct linux_binprm *bprm)
 	bprm->cred->euid = current_euid();
 	bprm->cred->egid = current_egid();
 
-	if (!mnt_may_suid(bprm->file->f_path.mnt))
+	if (path_nosuid(&bprm->file->f_path))
 		return;
 
 	if (task_no_new_privs(current))