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author | Jan Beulich <jbeulich@suse.com> | 2012-09-25 12:26:29 +0200 |
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committer | Jan Beulich <jbeulich@suse.com> | 2012-09-25 12:26:29 +0200 |
commit | a0c33932050cf9338479f6354315ea645a55bf82 (patch) | |
tree | e8adf82c53ab2bd56e1f7b0b0fee90b35c0ef264 | |
parent | 1266749162fd232c79898706f01082847a0e618e (diff) | |
download | xen-a0c33932050cf9338479f6354315ea645a55bf82.tar.gz xen-a0c33932050cf9338479f6354315ea645a55bf82.tar.bz2 xen-a0c33932050cf9338479f6354315ea645a55bf82.zip |
tmem: detect arithmetic overflow in tmh_copy_{from,to}_client()
This implies adjusting callers to deal with errors other than -EFAULT
and removing some comments which would otherwise become stale.
Reported-by: Tim Deegan <tim@xen.org>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
xen-unstable changeset: 25855:33b8c42a87ec
xen-unstable date: Tue Sep 11 12:17:59 UTC 2012
-rw-r--r-- | xen/common/tmem.c | 27 | ||||
-rw-r--r-- | xen/common/tmem_xen.c | 8 |
2 files changed, 19 insertions, 16 deletions
diff --git a/xen/common/tmem.c b/xen/common/tmem.c index ae02b379f7..b41f562ed6 100644 --- a/xen/common/tmem.c +++ b/xen/common/tmem.c @@ -1538,7 +1538,7 @@ copy_uncompressed: /* tmh_copy_from_client properly handles len==0 and offsets != 0 */ ret = tmh_copy_from_client(pgp->pfp, cmfn, tmem_offset, pfn_offset, len, tmh_cli_buf_null); - if ( ret == -EFAULT ) + if ( ret < 0 ) goto bad_copy; if ( tmh_dedup_enabled() && !is_persistent(pool) ) { @@ -1559,9 +1559,7 @@ done: return 1; bad_copy: - /* this should only happen if the client passed a bad mfn */ failed_copies++; - ret = -EFAULT; goto cleanup; failed_dup: @@ -1665,7 +1663,7 @@ copy_uncompressed: /* tmh_copy_from_client properly handles len==0 (TMEM_NEW_PAGE) */ ret = tmh_copy_from_client(pgp->pfp, cmfn, tmem_offset, pfn_offset, len, clibuf); - if ( ret == -EFAULT ) + if ( ret < 0 ) goto bad_copy; if ( tmh_dedup_enabled() && !is_persistent(pool) ) { @@ -1705,8 +1703,6 @@ insert_page: return 1; bad_copy: - /* this should only happen if the client passed a bad mfn */ - ret = -EFAULT; failed_copies++; delete_and_free: @@ -1740,7 +1736,7 @@ static NOINLINE int do_tmem_get(pool_t *pool, OID *oidp, uint32_t index, pgp_t *pgp; client_t *client = pool->client; DECL_LOCAL_CYC_COUNTER(decompress); - int rc = -EFAULT; + int rc; if ( !_atomic_read(pool->pgp_count) ) return -EEMPTY; @@ -1764,20 +1760,20 @@ static NOINLINE int do_tmem_get(pool_t *pool, OID *oidp, uint32_t index, ASSERT(pgp->size != -1); if ( tmh_dedup_enabled() && !is_persistent(pool) && pgp->firstbyte != NOT_SHAREABLE ) - { rc = pcd_copy_to_client(cmfn, pgp); - if ( rc <= 0 ) - goto bad_copy; - } else if ( pgp->size != 0 ) { + else if ( pgp->size != 0 ) + { START_CYC_COUNTER(decompress); rc = tmh_decompress_to_client(cmfn, pgp->cdata, pgp->size, clibuf); - if ( rc <= 0 ) - goto bad_copy; END_CYC_COUNTER(decompress); - } else if ( tmh_copy_to_client(cmfn, pgp->pfp, tmem_offset, - pfn_offset, len, clibuf) == -EFAULT) + } + else + rc = tmh_copy_to_client(cmfn, pgp->pfp, tmem_offset, + pfn_offset, len, clibuf); + if ( rc <= 0 ) goto bad_copy; + if ( is_ephemeral(pool) ) { if ( is_private(pool) ) @@ -1814,7 +1810,6 @@ static NOINLINE int do_tmem_get(pool_t *pool, OID *oidp, uint32_t index, return 1; bad_copy: - /* this should only happen if the client passed a bad mfn */ failed_copies++; return rc; } diff --git a/xen/common/tmem_xen.c b/xen/common/tmem_xen.c index bcd49f2afb..d549839cd6 100644 --- a/xen/common/tmem_xen.c +++ b/xen/common/tmem_xen.c @@ -148,6 +148,8 @@ EXPORT int tmh_copy_from_client(pfp_t *pfp, pfp_t *cli_pfp = NULL; int rc = 1; + if ( tmem_offset > PAGE_SIZE || pfn_offset > PAGE_SIZE || len > PAGE_SIZE ) + return -EINVAL; ASSERT(pfp != NULL); tmem_mfn = page_to_mfn(pfp); tmem_va = map_domain_page(tmem_mfn); @@ -178,6 +180,8 @@ EXPORT int tmh_copy_from_client(pfp_t *pfp, pfn_offset, len) ) rc = -EFAULT; } + else if ( len ) + rc = -EINVAL; if ( cli_va ) cli_put_page(cli_va, cli_pfp, cli_mfn, 0); unmap_domain_page(tmem_va); @@ -225,6 +229,8 @@ EXPORT int tmh_copy_to_client(tmem_cli_mfn_t cmfn, pfp_t *pfp, pfp_t *cli_pfp = NULL; int rc = 1; + if ( tmem_offset > PAGE_SIZE || pfn_offset > PAGE_SIZE || len > PAGE_SIZE ) + return -EINVAL; ASSERT(pfp != NULL); if ( guest_handle_is_null(clibuf) ) { @@ -244,6 +250,8 @@ EXPORT int tmh_copy_to_client(tmem_cli_mfn_t cmfn, pfp_t *pfp, tmem_va + tmem_offset, len) ) rc = -EFAULT; } + else if ( len ) + rc = -EINVAL; unmap_domain_page(tmem_va); if ( cli_va ) cli_put_page(cli_va, cli_pfp, cli_mfn, 1); |