[dpdk-stable] patch 'eal: copy raw strings taken from command line' has been queued to LTS release 16.11.4

luca.boccassi at gmail.com luca.boccassi at gmail.com
Mon Oct 30 16:34:44 CET 2017


FYI, your patch has been queued to LTS release 16.11.4

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 11/01/17. So please
shout if anyone has objections.


Kind regards,
Luca Boccassi

>From 4f267d69a21e9d7a55c67981087e0645ca021109 Mon Sep 17 00:00:00 2001
From: Patrick MacArthur <patrick at patrickmacarthur.net>
Date: Fri, 4 Aug 2017 14:53:57 -0400
Subject: [PATCH] eal: copy raw strings taken from command line

[ upstream commit e3f141879ef480c9e72e95d179c0879aed461406 ]

Normally, command line argument strings are considered immutable, but
SPDK [1] and urdma [2] construct argv arrays to pass to rte_eal_init().
These strings are allocated using malloc() and freed after DPDK
initialization with free(). However, in the case of --file-prefix and
--huge-dir, DPDK takes the pointer to these strings in argv directly. If
a secondary process calls rte_eal_pci_probe() after rte_eal_init()
returns, as is done by SPDK, this causes a use-after-free error because
the strings have been freed by the calling code immediately after
rte_eal_init() returns.

This problem was observed when running SPDK example programs as a
secondary process and causes the secondary processes to fail:

Starting DPDK 16.11.1 initialization...
[ DPDK EAL parameters: identify -c 4 --file-prefix=spdk3260 --base-virtaddr=0x1000000000 --proc-type=auto ]
EAL: Detected 40 lcore(s)
EAL: Auto-detected process type: SECONDARY
EAL: Probing VFIO support...
EAL: VFIO support initialized
EAL: PCI device 0000:81:00.0 on NUMA socket 1
EAL:   probe driver: 8086:953 spdk_nvme
EAL:   cannot connect to primary process!
EAL: Error - exiting with code: 1
Cause: Requested device 0000:81:00.0 cannot be used

Running strace shows that the file prefix has been zero'd out by the
time that the secondary process attempts to probe the NVMe device.

The use-after-free errors can be easily detected with valgrind:

==8489== Invalid read of size 1
==8489==    at 0x4C30D22: strlen (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==8489==    by 0x58DB955: vfprintf (vfprintf.c:1637)
==8489==    by 0x59A4685: __vsnprintf_chk (vsnprintf_chk.c:63)
==8489==    by 0x59A45E7: __snprintf_chk (snprintf_chk.c:34)
==8489==    by 0x1246AB: get_socket_path.constprop.0 (in /home/pmacarth/src/spdk/examples/nvme/identify/identify)
==8489==    by 0x124B09: vfio_mp_sync_connect_to_primary (in /home/pmacarth/src/spdk/examples/nvme/identify/identify)
==8489==    by 0x123BE4: vfio_get_group_fd.part.1 (in /home/pmacarth/src/spdk/examples/nvme/identify/identify)
==8489==    by 0x124366: vfio_setup_device (in /home/pmacarth/src/spdk/examples/nvme/identify/identify)
==8489==    by 0x126C8A: pci_vfio_map_resource (in /home/pmacarth/src/spdk/examples/nvme/identify/identify)
==8489==    by 0x12B115: pci_probe_all_drivers.part.0 (in /home/pmacarth/src/spdk/examples/nvme/identify/identify)
==8489==    by 0x12B596: rte_eal_pci_probe (in /home/pmacarth/src/spdk/examples/nvme/identify/identify)
==8489==    by 0x11D5B5: spdk_pci_enumerate (pci.c:147)
==8489==  Address 0x63f362e is 14 bytes inside a block of size 32 free'd
==8489==    at 0x4C2ED5B: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==8489==    by 0x11E6FB: spdk_free_args (init.c:136)
==8489==    by 0x11EBF5: spdk_env_init (init.c:309)
==8489==    by 0x10D2AA: main (identify.c:976)
==8489==  Block was alloc'd at
==8489==    at 0x4C2DB2F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==8489==    by 0x11E7D7: _sprintf_alloc (init.c:76)
==8489==    by 0x11EA78: spdk_build_eal_cmdline (init.c:251)
==8489==    by 0x11EA78: spdk_env_init (init.c:282)
==8489==    by 0x10D2AA: main (identify.c:976)

Fix this by using strdup() to create separate memory buffers for these
strings. Note that this patch will cause valgrind to report memory
leaks of these buffers as there is nowhere to free them. Using static
buffers is an option but would make these strings have a fixed maximum
length whereas there is currently no limit defined by the API.

[1] http://spdk.io
[2] https://github.com/zrlio/urdma

Fixes: af75078fece3 ("first public release")

Signed-off-by: Patrick MacArthur <patrick at patrickmacarthur.net>
Acked-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy at intel.com>
 lib/librte_eal/linuxapp/eal/eal.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
index 2075282e2..59ed78823 100644
--- a/lib/librte_eal/linuxapp/eal/eal.c
+++ b/lib/librte_eal/linuxapp/eal/eal.c
@@ -570,11 +570,11 @@ eal_parse_args(int argc, char **argv)
-			internal_config.hugepage_dir = optarg;
+			internal_config.hugepage_dir = strdup(optarg);
-			internal_config.hugefile_prefix = optarg;
+			internal_config.hugefile_prefix = strdup(optarg);

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