blob: c32f1141d807d6a8684e36c7c0887dc4d642098e [file] [log] [blame]
From c9452f9de240ada870977e39f8e65951120a221c Mon Sep 17 00:00:00 2001
From: Stephen Rothwell <sfr@canb.auug.org.au>
Date: Thu, 9 Jan 2020 18:39:12 +1100
Subject: [PATCH] tty: evh_bytechan: Fix out of bounds accesses
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commit 3670664b5da555a2a481449b3baafff113b0ac35 upstream.
ev_byte_channel_send() assumes that its third argument is a 16 byte
array. Some places where it is called it may not be (or we can't
easily tell if it is). Newer compilers have started producing warnings
about this, so make sure we actually pass a 16 byte array.
There may be more elegant solutions to this, but the driver is quite
old and hasn't been updated in many years.
The warnings (from a powerpc allyesconfig build) are:
In file included from include/linux/byteorder/big_endian.h:5,
from arch/powerpc/include/uapi/asm/byteorder.h:14,
from include/asm-generic/bitops/le.h:6,
from arch/powerpc/include/asm/bitops.h:250,
from include/linux/bitops.h:29,
from include/linux/kernel.h:12,
from include/asm-generic/bug.h:19,
from arch/powerpc/include/asm/bug.h:109,
from include/linux/bug.h:5,
from include/linux/mmdebug.h:5,
from include/linux/gfp.h:5,
from include/linux/slab.h:15,
from drivers/tty/ehv_bytechan.c:24:
drivers/tty/ehv_bytechan.c: In function ehv_bc_udbg_putc’:
arch/powerpc/include/asm/epapr_hcalls.h:298:20: warning: array subscript 1 is outside array bounds of const char[1]’ [-Warray-bounds]
298 | r6 = be32_to_cpu(p[1]);
include/uapi/linux/byteorder/big_endian.h:40:51: note: in definition of macro __be32_to_cpu
40 | #define __be32_to_cpu(x) ((__force __u32)(__be32)(x))
| ^
arch/powerpc/include/asm/epapr_hcalls.h:298:7: note: in expansion of macro be32_to_cpu
298 | r6 = be32_to_cpu(p[1]);
| ^~~~~~~~~~~
drivers/tty/ehv_bytechan.c:166:13: note: while referencing data
166 | static void ehv_bc_udbg_putc(char c)
| ^~~~~~~~~~~~~~~~
Fixes: dcd83aaff1c8 ("tty/powerpc: introduce the ePAPR embedded hypervisor byte channel driver")
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Tested-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
[mpe: Trim warnings from change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200109183912.5fcb52aa@canb.auug.org.au
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/tty/ehv_bytechan.c b/drivers/tty/ehv_bytechan.c
index 769e0a5d1dfc..3c6dd06ec5fb 100644
--- a/drivers/tty/ehv_bytechan.c
+++ b/drivers/tty/ehv_bytechan.c
@@ -136,6 +136,21 @@ static int find_console_handle(void)
return 1;
}
+static unsigned int local_ev_byte_channel_send(unsigned int handle,
+ unsigned int *count,
+ const char *p)
+{
+ char buffer[EV_BYTE_CHANNEL_MAX_BYTES];
+ unsigned int c = *count;
+
+ if (c < sizeof(buffer)) {
+ memcpy(buffer, p, c);
+ memset(&buffer[c], 0, sizeof(buffer) - c);
+ p = buffer;
+ }
+ return ev_byte_channel_send(handle, count, p);
+}
+
/*************************** EARLY CONSOLE DRIVER ***************************/
#ifdef CONFIG_PPC_EARLY_DEBUG_EHV_BC
@@ -154,7 +169,7 @@ static void byte_channel_spin_send(const char data)
do {
count = 1;
- ret = ev_byte_channel_send(CONFIG_PPC_EARLY_DEBUG_EHV_BC_HANDLE,
+ ret = local_ev_byte_channel_send(CONFIG_PPC_EARLY_DEBUG_EHV_BC_HANDLE,
&count, &data);
} while (ret == EV_EAGAIN);
}
@@ -221,7 +236,7 @@ static int ehv_bc_console_byte_channel_send(unsigned int handle, const char *s,
while (count) {
len = min_t(unsigned int, count, EV_BYTE_CHANNEL_MAX_BYTES);
do {
- ret = ev_byte_channel_send(handle, &len, s);
+ ret = local_ev_byte_channel_send(handle, &len, s);
} while (ret == EV_EAGAIN);
count -= len;
s += len;
@@ -401,7 +416,7 @@ static void ehv_bc_tx_dequeue(struct ehv_bc_data *bc)
CIRC_CNT_TO_END(bc->head, bc->tail, BUF_SIZE),
EV_BYTE_CHANNEL_MAX_BYTES);
- ret = ev_byte_channel_send(bc->handle, &len, bc->buf + bc->tail);
+ ret = local_ev_byte_channel_send(bc->handle, &len, bc->buf + bc->tail);
/* 'len' is valid only if the return code is 0 or EV_EAGAIN */
if (!ret || (ret == EV_EAGAIN))
--
2.7.4