Merge 4.4.199 into android-4.4-p

Changes in 4.4.199
	dm snapshot: use mutex instead of rw_semaphore
	dm snapshot: introduce account_start_copy() and account_end_copy()
	dm snapshot: rework COW throttling to fix deadlock
	dm: Use kzalloc for all structs with embedded biosets/mempools
	sc16is7xx: Fix for "Unexpected interrupt: 8"
	x86/cpu: Add Atom Tremont (Jacobsville)
	scripts/setlocalversion: Improve -dirty check with git-status --no-optional-locks
	usb: handle warm-reset port requests on hub resume
	exec: load_script: Do not exec truncated interpreter path
	iio: fix center temperature of bmc150-accel-core
	perf map: Fix overlapped map handling
	RDMA/iwcm: Fix a lock inversion issue
	fs: cifs: mute -Wunused-const-variable message
	serial: mctrl_gpio: Check for NULL pointer
	efi/cper: Fix endianness of PCIe class code
	efi/x86: Do not clean dummy variable in kexec path
	fs: ocfs2: fix possible null-pointer dereferences in ocfs2_xa_prepare_entry()
	fs: ocfs2: fix a possible null-pointer dereference in ocfs2_info_scan_inode_alloc()
	MIPS: fw: sni: Fix out of bounds init of o32 stack
	NFSv4: Fix leak of clp->cl_acceptor string
	tracing: Initialize iter->seq after zeroing in tracing_read_pipe()
	USB: legousbtower: fix a signedness bug in tower_probe()
	thunderbolt: Use 32-bit writes when writing ring producer/consumer
	ath6kl: fix a NULL-ptr-deref bug in ath6kl_usb_alloc_urb_from_pipe()
	fuse: flush dirty data/metadata before non-truncate setattr
	fuse: truncate pending writes on O_TRUNC
	ALSA: bebob: Fix prototype of helper function to return negative value
	UAS: Revert commit 3ae62a42090f ("UAS: fix alignment of scatter/gather segments")
	USB: gadget: Reject endpoints with 0 maxpacket value
	USB: ldusb: fix ring-buffer locking
	USB: ldusb: fix control-message timeout
	USB: serial: whiteheat: fix potential slab corruption
	USB: serial: whiteheat: fix line-speed endianness
	HID: Fix assumption that devices have inputs
	HID: fix error message in hid_open_report()
	nl80211: fix validation of mesh path nexthop
	s390/cmm: fix information leak in cmm_timeout_handler()
	rtlwifi: Fix potential overflow on P2P code
	llc: fix sk_buff leak in llc_sap_state_process()
	llc: fix sk_buff leak in llc_conn_service()
	bonding: fix potential NULL deref in bond_update_slave_arr
	net: usb: sr9800: fix uninitialized local variable
	sch_netem: fix rcu splat in netem_enqueue()
	sctp: fix the issue that flags are ignored when using kernel_connect
	sctp: not bind the socket in sctp_connect
	xfs: Correctly invert xfs_buftarg LRU isolation logic
	Revert "ALSA: hda: Flush interrupts on disabling"
	Linux 4.4.199

Change-Id: Ia26458456401f9ec050f4c11bd5bdf24b8a21b24
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

1 files changed, 48 insertions, 9 deletions

diff --git a/fs/binfmt_script.c b/fs/binfmt_script.c
index afdf4e3cafc2..37c2093a24d3 100644
--- a/fs/binfmt_script.c
+++ b/fs/binfmt_script.c
@@ -14,14 +14,31 @@
 #include <linux/err.h>
 #include <linux/fs.h>
 
+static inline bool spacetab(char c) { return c == ' ' || c == '\t'; }
+static inline char *next_non_spacetab(char *first, const char *last)
+{
+	for (; first <= last; first++)
+		if (!spacetab(*first))
+			return first;
+	return NULL;
+}
+static inline char *next_terminator(char *first, const char *last)
+{
+	for (; first <= last; first++)
+		if (spacetab(*first) || !*first)
+			return first;
+	return NULL;
+}
+
 static int load_script(struct linux_binprm *bprm)
 {
 	const char *i_arg, *i_name;
-	char *cp;
+	char *cp, *buf_end;
 	struct file *file;
 	char interp[BINPRM_BUF_SIZE];
 	int retval;
 
+	/* Not ours to exec if we don't start with "#!". */
 	if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!'))
 		return -ENOEXEC;
 
@@ -34,18 +51,40 @@ static int load_script(struct linux_binprm *bprm)
 	if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
 		return -ENOENT;
 
-	/*
-	 * This section does the #! interpretation.
-	 * Sorta complicated, but hopefully it will work.  -TYT
-	 */
-
+	/* Release since we are not mapping a binary into memory. */
 	allow_write_access(bprm->file);
 	fput(bprm->file);
 	bprm->file = NULL;
 
-	bprm->buf[BINPRM_BUF_SIZE - 1] = '\0';
-	if ((cp = strchr(bprm->buf, '\n')) == NULL)
-		cp = bprm->buf+BINPRM_BUF_SIZE-1;
+	/*
+	 * This section handles parsing the #! line into separate
+	 * interpreter path and argument strings. We must be careful
+	 * because bprm->buf is not yet guaranteed to be NUL-terminated
+	 * (though the buffer will have trailing NUL padding when the
+	 * file size was smaller than the buffer size).
+	 *
+	 * We do not want to exec a truncated interpreter path, so either
+	 * we find a newline (which indicates nothing is truncated), or
+	 * we find a space/tab/NUL after the interpreter path (which
+	 * itself may be preceded by spaces/tabs). Truncating the
+	 * arguments is fine: the interpreter can re-read the script to
+	 * parse them on its own.
+	 */
+	buf_end = bprm->buf + sizeof(bprm->buf) - 1;
+	cp = strnchr(bprm->buf, sizeof(bprm->buf), '\n');
+	if (!cp) {
+		cp = next_non_spacetab(bprm->buf + 2, buf_end);
+		if (!cp)
+			return -ENOEXEC; /* Entire buf is spaces/tabs */
+		/*
+		 * If there is no later space/tab/NUL we must assume the
+		 * interpreter path is truncated.
+		 */
+		if (!next_terminator(cp, buf_end))
+			return -ENOEXEC;
+		cp = buf_end;
+	}
+	/* NUL-terminate the buffer and any trailing spaces/tabs. */
 	*cp = '\0';
 	while (cp > bprm->buf) {
 		cp--;