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| author | Laura Abbott <labbott@redhat.com> | 2016-09-20 08:56:36 -0700 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2016-09-20 16:07:39 -0700 |
| commit | aa4f0601115319a52c80f468c8f007e5aa9277cb (patch) | |
| tree | c09b301bdbf5cbcb44805fb0698d7270e1bc51c9 | |
| parent | d2ffb0103aaefa9b169da042cf39ce27bfb6cdbb (diff) | |
| download | linux-aa4f0601115319a52c80f468c8f007e5aa9277cb.tar.gz linux-aa4f0601115319a52c80f468c8f007e5aa9277cb.tar.bz2 linux-aa4f0601115319a52c80f468c8f007e5aa9277cb.zip | |
mm: usercopy: Check for module addresses
While running a compile on arm64, I hit a memory exposure
usercopy: kernel memory exposure attempt detected from fffffc0000f3b1a8 (buffer_head) (1 bytes)
------------[ cut here ]------------
kernel BUG at mm/usercopy.c:75!
Internal error: Oops - BUG: 0 [#1] SMP
Modules linked in: ip6t_rpfilter ip6t_REJECT
nf_reject_ipv6 xt_conntrack ip_set nfnetlink ebtable_broute bridge stp
llc ebtable_nat ip6table_security ip6table_raw ip6table_nat
nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle
iptable_security iptable_raw iptable_nat nf_conntrack_ipv4
nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle
ebtable_filter ebtables ip6table_filter ip6_tables vfat fat xgene_edac
xgene_enet edac_core i2c_xgene_slimpro i2c_core at803x realtek xgene_dma
mdio_xgene gpio_dwapb gpio_xgene_sb xgene_rng mailbox_xgene_slimpro nfsd
auth_rpcgss nfs_acl lockd grace sunrpc xfs libcrc32c sdhci_of_arasan
sdhci_pltfm sdhci mmc_core xhci_plat_hcd gpio_keys
CPU: 0 PID: 19744 Comm: updatedb Tainted: G W 4.8.0-rc3-threadinfo+ #1
Hardware name: AppliedMicro X-Gene Mustang Board/X-Gene Mustang Board, BIOS 3.06.12 Aug 12 2016
task: fffffe03df944c00 task.stack: fffffe00d128c000
PC is at __check_object_size+0x70/0x3f0
LR is at __check_object_size+0x70/0x3f0
...
[<fffffc00082b4280>] __check_object_size+0x70/0x3f0
[<fffffc00082cdc30>] filldir64+0x158/0x1a0
[<fffffc0000f327e8>] __fat_readdir+0x4a0/0x558 [fat]
[<fffffc0000f328d4>] fat_readdir+0x34/0x40 [fat]
[<fffffc00082cd8f8>] iterate_dir+0x190/0x1e0
[<fffffc00082cde58>] SyS_getdents64+0x88/0x120
[<fffffc0008082c70>] el0_svc_naked+0x24/0x28
fffffc0000f3b1a8 is a module address. Modules may have compiled in
strings which could get copied to userspace. In this instance, it
looks like "." which matches with a size of 1 byte. Extend the
is_vmalloc_addr check to be is_vmalloc_or_module_addr to cover
all possible cases.
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
| -rw-r--r-- | mm/usercopy.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/mm/usercopy.c b/mm/usercopy.c index 089328f2b920..3c8da0af9695 100644 --- a/mm/usercopy.c +++ b/mm/usercopy.c @@ -207,8 +207,11 @@ static inline const char *check_heap_object(const void *ptr, unsigned long n, * Some architectures (arm64) return true for virt_addr_valid() on * vmalloced addresses. Work around this by checking for vmalloc * first. + * + * We also need to check for module addresses explicitly since we + * may copy static data from modules to userspace */ - if (is_vmalloc_addr(ptr)) + if (is_vmalloc_or_module_addr(ptr)) return NULL; if (!virt_addr_valid(ptr)) |