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gentoo-full-overlay/app-emulation/xen-tools/files/xen-4.2-CVE-2013-18to19-XSA...

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From b06e277b1fc08c7da3befeb3ac3950e1d941585d Mon Sep 17 00:00:00 2001
From: Ian Jackson <ian.jackson@eu.citrix.com>
Date: Fri, 14 Jun 2013 16:43:19 +0100
Subject: [PATCH 18/23] libxc: Add range checking to xc_dom_binloader
This is a simple binary image loader with its own metadata format.
However, it is too careless with image-supplied values.
Add the following checks:
* That the image is bigger than the metadata table; otherwise the
pointer arithmetic to calculate the metadata table location may
yield undefined and dangerous values.
* When clamping the end of the region to search, that we do not
calculate pointers beyond the end of the image. The C
specification does not permit this and compilers are becoming ever
more determined to miscompile code when they can "prove" various
falsehoods based on assertions from the C spec.
* That the supplied image is big enough for the text we are allegedly
copying from it. Otherwise we might have a read overrun and copy
the results (perhaps a lot of secret data) into the guest.
This is part of the fix to a security issue, XSA-55.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
---
tools/libxc/xc_dom_binloader.c | 15 +++++++++++++--
1 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/tools/libxc/xc_dom_binloader.c b/tools/libxc/xc_dom_binloader.c
index bde93f7..8596a28 100644
--- a/tools/libxc/xc_dom_binloader.c
+++ b/tools/libxc/xc_dom_binloader.c
@@ -123,10 +123,13 @@ static struct xen_bin_image_table *find_table(struct xc_dom_image *dom)
uint32_t *probe_ptr;
uint32_t *probe_end;
+ if ( dom->kernel_size < sizeof(*table) )
+ return NULL;
probe_ptr = dom->kernel_blob;
- probe_end = dom->kernel_blob + dom->kernel_size - sizeof(*table);
- if ( (void*)probe_end > (dom->kernel_blob + 8192) )
+ if ( dom->kernel_size > (8192 + sizeof(*table)) )
probe_end = dom->kernel_blob + 8192;
+ else
+ probe_end = dom->kernel_blob + dom->kernel_size - sizeof(*table);
for ( table = NULL; probe_ptr < probe_end; probe_ptr++ )
{
@@ -282,6 +285,14 @@ static int xc_dom_load_bin_kernel(struct xc_dom_image *dom)
return -EINVAL;
}
+ if ( image_size < skip ||
+ image_size - skip < text_size )
+ {
+ DOMPRINTF("%s: image is too small for declared text size",
+ __FUNCTION__);
+ return -EINVAL;
+ }
+
memcpy(dest, image + skip, text_size);
memset(dest + text_size, 0, bss_size);
--
1.7.2.5
#From 77c0829fa751f052f7b8ec08287aef6e7ba97bc5 Mon Sep 17 00:00:00 2001
#From: Ian Jackson <ian.jackson@eu.citrix.com>
#Date: Fri, 14 Jun 2013 16:43:19 +0100
#Subject: [PATCH 19/23] libxc: check failure of xc_dom_*_to_ptr, xc_map_foreign_range
#
#The return values from xc_dom_*_to_ptr and xc_map_foreign_range are
#sometimes dereferenced, or subjected to pointer arithmetic, without
#checking whether the relevant function failed and returned NULL.
#
#Add an appropriate error check at every call site.
#
#Changes in the 4.2 backport of this series:
#* Fix tools/libxc/xc_dom_x86.c:setup_pgtables_x86_32.
#* Fix tools/libxc/xc_dom_ia64.c:start_info_ia64.
#* Fix tools/libxc/ia64/xc_ia64_dom_fwloader.c:xc_dom_load_fw_kernel.
#
#This is part of the fix to a security issue, XSA-55.
#
#Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
#---
# tools/libxc/ia64/xc_ia64_dom_fwloader.c | 2 +
# tools/libxc/xc_dom_binloader.c | 6 +++
# tools/libxc/xc_dom_core.c | 6 +++
# tools/libxc/xc_dom_elfloader.c | 13 +++++++
# tools/libxc/xc_dom_ia64.c | 6 +++
# tools/libxc/xc_dom_x86.c | 55 +++++++++++++++++++++++++++++++
# tools/libxc/xc_domain_restore.c | 27 +++++++++++++++
# tools/libxc/xc_offline_page.c | 5 +++
# 8 files changed, 120 insertions(+), 0 deletions(-)
#
diff --git a/tools/libxc/ia64/xc_ia64_dom_fwloader.c b/tools/libxc/ia64/xc_ia64_dom_fwloader.c
index cdf3333..dbd3349 100644
--- a/tools/libxc/ia64/xc_ia64_dom_fwloader.c
+++ b/tools/libxc/ia64/xc_ia64_dom_fwloader.c
@@ -60,6 +60,8 @@ static int xc_dom_load_fw_kernel(struct xc_dom_image *dom)
unsigned long i;
dest = xc_dom_vaddr_to_ptr(dom, dom->kernel_seg.vstart);
+ if ( dest == NULL )
+ return -1;
memcpy(dest, dom->kernel_blob, FW_SIZE);
/* Synchronize cache. */
diff --git a/tools/libxc/xc_dom_binloader.c b/tools/libxc/xc_dom_binloader.c
index 8596a28..553b366 100644
--- a/tools/libxc/xc_dom_binloader.c
+++ b/tools/libxc/xc_dom_binloader.c
@@ -277,6 +277,12 @@ static int xc_dom_load_bin_kernel(struct xc_dom_image *dom)
DOMPRINTF(" bss_size: 0x%" PRIx32 "", bss_size);
dest = xc_dom_vaddr_to_ptr(dom, dom->kernel_seg.vstart, &dest_size);
+ if ( dest == NULL )
+ {
+ DOMPRINTF("%s: xc_dom_vaddr_to_ptr(dom, dom->kernel_seg.vstart)"
+ " => NULL", __FUNCTION__);
+ return -EINVAL;
+ }
if ( dest_size < text_size ||
dest_size - text_size < bss_size )
diff --git a/tools/libxc/xc_dom_core.c b/tools/libxc/xc_dom_core.c
index 8913e41..a54ddae 100644
--- a/tools/libxc/xc_dom_core.c
+++ b/tools/libxc/xc_dom_core.c
@@ -868,6 +868,12 @@ int xc_dom_build_image(struct xc_dom_image *dom)
ramdisklen) != 0 )
goto err;
ramdiskmap = xc_dom_seg_to_ptr(dom, &dom->ramdisk_seg);
+ if ( ramdiskmap == NULL )
+ {
+ DOMPRINTF("%s: xc_dom_seg_to_ptr(dom, &dom->ramdisk_seg) => NULL",
+ __FUNCTION__);
+ goto err;
+ }
if ( unziplen )
{
if ( xc_dom_do_gunzip(dom->xch,
diff --git a/tools/libxc/xc_dom_elfloader.c b/tools/libxc/xc_dom_elfloader.c
index 9fc4b94..61b5798 100644
--- a/tools/libxc/xc_dom_elfloader.c
+++ b/tools/libxc/xc_dom_elfloader.c
@@ -139,6 +139,12 @@ static elf_errorstatus xc_dom_load_elf_symtab(struct xc_dom_image *dom,
return 0;
size = dom->kernel_seg.vend - dom->bsd_symtab_start;
hdr_ptr = xc_dom_vaddr_to_ptr(dom, dom->bsd_symtab_start, &allow_size);
+ if ( hdr_ptr == NULL )
+ {
+ DOMPRINTF("%s/load: xc_dom_vaddr_to_ptr(dom,dom->bsd_symtab_start"
+ " => NULL", __FUNCTION__);
+ return -1;
+ }
elf->caller_xdest_base = hdr_ptr;
elf->caller_xdest_size = allow_size;
hdr = ELF_REALPTR2PTRVAL(hdr_ptr);
@@ -384,7 +390,14 @@ static elf_errorstatus xc_dom_load_elf_kernel(struct xc_dom_image *dom)
xen_pfn_t pages;
elf->dest_base = xc_dom_seg_to_ptr_pages(dom, &dom->kernel_seg, &pages);
+ if ( elf->dest_base == NULL )
+ {
+ DOMPRINTF("%s: xc_dom_vaddr_to_ptr(dom,dom->kernel_seg)"
+ " => NULL", __FUNCTION__);
+ return -1;
+ }
elf->dest_size = pages * XC_DOM_PAGE_SIZE(dom);
+
rc = elf_load_binary(elf);
if ( rc < 0 )
{
diff --git a/tools/libxc/xc_dom_ia64.c b/tools/libxc/xc_dom_ia64.c
index dcd1523..7c0eff1 100644
--- a/tools/libxc/xc_dom_ia64.c
+++ b/tools/libxc/xc_dom_ia64.c
@@ -60,6 +60,12 @@ int start_info_ia64(struct xc_dom_image *dom)
DOMPRINTF_CALLED(dom->xch);
+ if ( start_info == NULL )
+ {
+ DOMPRINTF("%s: xc_dom_pfn_to_ptr failed on start_info", __FUNCTION__);
+ return -1; /* our caller throws away our return value :-/ */
+ }
+
memset(start_info, 0, sizeof(*start_info));
sprintf(start_info->magic, dom->guest_type);
start_info->flags = dom->flags;
diff --git a/tools/libxc/xc_dom_x86.c b/tools/libxc/xc_dom_x86.c
index 0cf1687..75d6b83 100644
--- a/tools/libxc/xc_dom_x86.c
+++ b/tools/libxc/xc_dom_x86.c
@@ -144,6 +144,9 @@ static int setup_pgtables_x86_32(struct xc_dom_image *dom)
xen_vaddr_t addr;
xen_pfn_t pgpfn;
+ if ( l2tab == NULL )
+ goto pfn_error;
+
for ( addr = dom->parms.virt_base; addr < dom->virt_pgtab_end;
addr += PAGE_SIZE_X86 )
{
@@ -151,6 +154,8 @@ static int setup_pgtables_x86_32(struct xc_dom_image *dom)
{
/* get L1 tab, make L2 entry */
l1tab = xc_dom_pfn_to_ptr(dom, l1pfn, 1);
+ if ( l1tab == NULL )
+ goto pfn_error;
l2off = l2_table_offset_i386(addr);
l2tab[l2off] =
pfn_to_paddr(xc_dom_p2m_guest(dom, l1pfn)) | L2_PROT;
@@ -169,6 +174,11 @@ static int setup_pgtables_x86_32(struct xc_dom_image *dom)
l1tab = NULL;
}
return 0;
+
+pfn_error:
+ xc_dom_panic(dom->xch, XC_INTERNAL_ERROR,
+ "%s: xc_dom_pfn_to_ptr failed", __FUNCTION__);
+ return -EINVAL;
}
/*
@@ -219,6 +229,12 @@ static xen_pfn_t move_l3_below_4G(struct xc_dom_image *dom,
goto out;
l3tab = xc_dom_pfn_to_ptr(dom, l3pfn, 1);
+ if ( l3tab == NULL )
+ {
+ DOMPRINTF("%s: xc_dom_pfn_to_ptr(dom, l3pfn, 1) => NULL",
+ __FUNCTION__);
+ return l3mfn; /* our one call site will call xc_dom_panic and fail */
+ }
memset(l3tab, 0, XC_DOM_PAGE_SIZE(dom));
DOMPRINTF("%s: successfully relocated L3 below 4G. "
@@ -262,6 +278,8 @@ static int setup_pgtables_x86_32_pae(struct xc_dom_image *dom)
}
l3tab = xc_dom_pfn_to_ptr(dom, l3pfn, 1);
+ if ( l3tab == NULL )
+ goto pfn_error;
for ( addr = dom->parms.virt_base; addr < dom->virt_pgtab_end;
addr += PAGE_SIZE_X86 )
@@ -270,6 +288,8 @@ static int setup_pgtables_x86_32_pae(struct xc_dom_image *dom)
{
/* get L2 tab, make L3 entry */
l2tab = xc_dom_pfn_to_ptr(dom, l2pfn, 1);
+ if ( l2tab == NULL )
+ goto pfn_error;
l3off = l3_table_offset_pae(addr);
l3tab[l3off] =
pfn_to_paddr(xc_dom_p2m_guest(dom, l2pfn)) | L3_PROT;
@@ -280,6 +300,8 @@ static int setup_pgtables_x86_32_pae(struct xc_dom_image *dom)
{
/* get L1 tab, make L2 entry */
l1tab = xc_dom_pfn_to_ptr(dom, l1pfn, 1);
+ if ( l1tab == NULL )
+ goto pfn_error;
l2off = l2_table_offset_pae(addr);
l2tab[l2off] =
pfn_to_paddr(xc_dom_p2m_guest(dom, l1pfn)) | L2_PROT;
@@ -306,6 +328,11 @@ static int setup_pgtables_x86_32_pae(struct xc_dom_image *dom)
l3tab[3] = pfn_to_paddr(xc_dom_p2m_guest(dom, l2pfn)) | L3_PROT;
}
return 0;
+
+pfn_error:
+ xc_dom_panic(dom->xch, XC_INTERNAL_ERROR,
+ "%s: xc_dom_pfn_to_ptr failed", __FUNCTION__);
+ return -EINVAL;
}
#undef L1_PROT
@@ -344,6 +371,9 @@ static int setup_pgtables_x86_64(struct xc_dom_image *dom)
uint64_t addr;
xen_pfn_t pgpfn;
+ if ( l4tab == NULL )
+ goto pfn_error;
+
for ( addr = dom->parms.virt_base; addr < dom->virt_pgtab_end;
addr += PAGE_SIZE_X86 )
{
@@ -351,6 +381,8 @@ static int setup_pgtables_x86_64(struct xc_dom_image *dom)
{
/* get L3 tab, make L4 entry */
l3tab = xc_dom_pfn_to_ptr(dom, l3pfn, 1);
+ if ( l3tab == NULL )
+ goto pfn_error;
l4off = l4_table_offset_x86_64(addr);
l4tab[l4off] =
pfn_to_paddr(xc_dom_p2m_guest(dom, l3pfn)) | L4_PROT;
@@ -361,6 +393,8 @@ static int setup_pgtables_x86_64(struct xc_dom_image *dom)
{
/* get L2 tab, make L3 entry */
l2tab = xc_dom_pfn_to_ptr(dom, l2pfn, 1);
+ if ( l2tab == NULL )
+ goto pfn_error;
l3off = l3_table_offset_x86_64(addr);
l3tab[l3off] =
pfn_to_paddr(xc_dom_p2m_guest(dom, l2pfn)) | L3_PROT;
@@ -373,6 +407,8 @@ static int setup_pgtables_x86_64(struct xc_dom_image *dom)
{
/* get L1 tab, make L2 entry */
l1tab = xc_dom_pfn_to_ptr(dom, l1pfn, 1);
+ if ( l1tab == NULL )
+ goto pfn_error;
l2off = l2_table_offset_x86_64(addr);
l2tab[l2off] =
pfn_to_paddr(xc_dom_p2m_guest(dom, l1pfn)) | L2_PROT;
@@ -393,6 +429,11 @@ static int setup_pgtables_x86_64(struct xc_dom_image *dom)
l1tab = NULL;
}
return 0;
+
+pfn_error:
+ xc_dom_panic(dom->xch, XC_INTERNAL_ERROR,
+ "%s: xc_dom_pfn_to_ptr failed", __FUNCTION__);
+ return -EINVAL;
}
#undef L1_PROT
@@ -410,6 +451,8 @@ static int alloc_magic_pages(struct xc_dom_image *dom)
if ( xc_dom_alloc_segment(dom, &dom->p2m_seg, "phys2mach", 0, p2m_size) )
return -1;
dom->p2m_guest = xc_dom_seg_to_ptr(dom, &dom->p2m_seg);
+ if ( dom->p2m_guest == NULL )
+ return -1;
/* allocate special pages */
dom->start_info_pfn = xc_dom_alloc_page(dom, "start info");
@@ -434,6 +477,12 @@ static int start_info_x86_32(struct xc_dom_image *dom)
DOMPRINTF_CALLED(dom->xch);
+ if ( start_info == NULL )
+ {
+ DOMPRINTF("%s: xc_dom_pfn_to_ptr failed on start_info", __FUNCTION__);
+ return -1; /* our caller throws away our return value :-/ */
+ }
+
memset(start_info, 0, sizeof(*start_info));
strncpy(start_info->magic, dom->guest_type, sizeof(start_info->magic));
start_info->magic[sizeof(start_info->magic) - 1] = '\0';
@@ -474,6 +523,12 @@ static int start_info_x86_64(struct xc_dom_image *dom)
DOMPRINTF_CALLED(dom->xch);
+ if ( start_info == NULL )
+ {
+ DOMPRINTF("%s: xc_dom_pfn_to_ptr failed on start_info", __FUNCTION__);
+ return -1; /* our caller throws away our return value :-/ */
+ }
+
memset(start_info, 0, sizeof(*start_info));
strncpy(start_info->magic, dom->guest_type, sizeof(start_info->magic));
start_info->magic[sizeof(start_info->magic) - 1] = '\0';
diff --git a/tools/libxc/xc_domain_restore.c b/tools/libxc/xc_domain_restore.c
index b4c0b10..3994f8f 100644
--- a/tools/libxc/xc_domain_restore.c
+++ b/tools/libxc/xc_domain_restore.c
@@ -1556,6 +1556,12 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
mfn = ctx->p2m[pfn];
buf = xc_map_foreign_range(xch, dom, PAGE_SIZE,
PROT_READ | PROT_WRITE, mfn);
+ if ( buf == NULL )
+ {
+ ERROR("xc_map_foreign_range for generation id"
+ " buffer failed");
+ goto out;
+ }
generationid = *(unsigned long long *)(buf + offset);
*(unsigned long long *)(buf + offset) = generationid + 1;
@@ -1713,6 +1719,11 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
l3tab = (uint64_t *)
xc_map_foreign_range(xch, dom, PAGE_SIZE,
PROT_READ, ctx->p2m[i]);
+ if ( l3tab == NULL )
+ {
+ PERROR("xc_map_foreign_range failed (for l3tab)");
+ goto out;
+ }
for ( j = 0; j < 4; j++ )
l3ptes[j] = l3tab[j];
@@ -1739,6 +1750,11 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
l3tab = (uint64_t *)
xc_map_foreign_range(xch, dom, PAGE_SIZE,
PROT_READ | PROT_WRITE, ctx->p2m[i]);
+ if ( l3tab == NULL )
+ {
+ PERROR("xc_map_foreign_range failed (for l3tab, 2nd)");
+ goto out;
+ }
for ( j = 0; j < 4; j++ )
l3tab[j] = l3ptes[j];
@@ -1909,6 +1925,12 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
SET_FIELD(ctxt, user_regs.edx, mfn);
start_info = xc_map_foreign_range(
xch, dom, PAGE_SIZE, PROT_READ | PROT_WRITE, mfn);
+ if ( start_info == NULL )
+ {
+ PERROR("xc_map_foreign_range failed (for start_info)");
+ goto out;
+ }
+
SET_FIELD(start_info, nr_pages, dinfo->p2m_size);
SET_FIELD(start_info, shared_info, shared_info_frame<<PAGE_SHIFT);
SET_FIELD(start_info, flags, 0);
@@ -2056,6 +2078,11 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
/* Restore contents of shared-info page. No checking needed. */
new_shared_info = xc_map_foreign_range(
xch, dom, PAGE_SIZE, PROT_WRITE, shared_info_frame);
+ if ( new_shared_info == NULL )
+ {
+ PERROR("xc_map_foreign_range failed (for new_shared_info)");
+ goto out;
+ }
/* restore saved vcpu_info and arch specific info */
MEMCPY_FIELD(new_shared_info, old_shared_info, vcpu_info);
diff --git a/tools/libxc/xc_offline_page.c b/tools/libxc/xc_offline_page.c
index 089a361..36b9812 100644
--- a/tools/libxc/xc_offline_page.c
+++ b/tools/libxc/xc_offline_page.c
@@ -714,6 +714,11 @@ int xc_exchange_page(xc_interface *xch, int domid, xen_pfn_t mfn)
new_p = xc_map_foreign_range(xch, domid, PAGE_SIZE,
PROT_READ|PROT_WRITE, new_mfn);
+ if ( new_p == NULL )
+ {
+ ERROR("failed to map new_p for copy, guest may be broken?");
+ goto failed;
+ }
memcpy(new_p, backup, PAGE_SIZE);
munmap(new_p, PAGE_SIZE);
mops.arg1.mfn = new_mfn;
--
1.7.2.5
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