8:34 a.m.
[Resend as the original posting apaprnetly got stuck in the mail queue.]
This small patch series enhances support for VMware vmss dump and core
files by fixing some bugs I ran into.
I meanwhile realized that the register dump of patch 2 can also be seen
via 'help -r' but its formating fixes are useful nonetheless.
Please apply!
Thanks,
Mathias
Mathias Krause (3):
vmware: vmss - support huge holes in vmem
vmware: vmss - beautify and extend debug log
Support core files with "unusual" layout
netdump.c | 86 +++++++++++++++++++++++++++++++++++----------------
netdump.h | 2 ++
vmware_vmss.c | 18 +++++++++--
3 files changed, 76 insertions(+), 30 deletions(-)
--
2.20.1
8:34 a.m.
New subject: [PATCH 1/3] vmware: vmss - support huge holes in vmem
If the hole is big enough, the multiplication by page size will truncate
as it's operating on a uint32_t.
Cast to uint64_t before to avoid that.
Signed-off-by: Mathias Krause <minipli(a)grsecurity.net>
---
vmware_vmss.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/vmware_vmss.c b/vmware_vmss.c
index eed948f46ee3..11b7b72bf503 100644
--- a/vmware_vmss.c
+++ b/vmware_vmss.c
@@ -498,12 +498,14 @@ read_vmware_vmss(int fd, void *bufptr, int cnt, ulong addr,
physaddr_t paddr)
int i;
for (i = 0; i < vmss.regionscount; i++) {
+ uint32_t hole;
+
if (ppn < vmss.regions[i].startppn)
break;
/* skip holes. */
- pos -= ((vmss.regions[i].startppn - vmss.regions[i].startpagenum)
- << VMW_PAGE_SHIFT);
+ hole = vmss.regions[i].startppn - vmss.regions[i].startpagenum;
+ pos -= (uint64_t)hole << VMW_PAGE_SHIFT;
}
}
--
2.20.1
8:34 a.m.
New subject: [PATCH 2/3] vmware: vmss - beautify and extend debug log
The parser's debug log is missing a few line breaks as well as some
crucial information, like control register dumps.
Add them for read- and debugability.
Signed-off-by: Mathias Krause <minipli(a)grsecurity.net>
---
vmware_vmss.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/vmware_vmss.c b/vmware_vmss.c
index 11b7b72bf503..53745fd48527 100644
--- a/vmware_vmss.c
+++ b/vmware_vmss.c
@@ -175,8 +175,10 @@ vmware_vmss_init(char *filename, FILE *ofp)
}
DEBUG_PARSE_PRINT((ofp, "[%d]", idx[j]));
}
- if (nextgroup)
+ if (nextgroup) {
+ DEBUG_PARSE_PRINT((ofp, "\n"));
break;
+ }
if (IS_BLOCK_TAG(tag)) {
uint64_t nbytes;
@@ -232,16 +234,22 @@ vmware_vmss_init(char *filename, FILE *ofp)
filename, errno, strerror(errno));
break;
}
+ DEBUG_PARSE_PRINT((ofp, "\n"));
vmss.vcpu_regs[cpu] |= REGS_PRESENT_GPREGS;
} else if (strcmp(name, "CR64") == 0 &&
nbytes == VMW_CR64_SIZE &&
idx[0] < vmss.num_vcpus) {
int cpu = idx[0];
+ DEBUG_PARSE_PRINT((ofp, "\t=> "));
if (fread(&vmss.regs64[cpu]->cr[0], VMW_CR64_SIZE, 1, fp) != 1) {
error(INFO, LOGPRX"Failed to read '%s': [Error %d] %s\n",
filename, errno, strerror(errno));
break;
}
+ for (j = 0; j < VMW_CR64_SIZE / 8; j++) {
+ DEBUG_PARSE_PRINT((ofp, "%s%016llX", j ? " " : "",
vmss.regs64[cpu]->cr[j]));
+ }
+ DEBUG_PARSE_PRINT((ofp, "\n"));
vmss.vcpu_regs[cpu] |= REGS_PRESENT_CRS;
} else if (strcmp(name, "IDTR") == 0 &&
nbytes == VMW_IDTR_SIZE &&
@@ -258,6 +266,7 @@ vmware_vmss_init(char *filename, FILE *ofp)
filename, errno, strerror(errno));
break;
}
+ DEBUG_PARSE_PRINT((ofp, "\n"));
vmss.regs64[cpu]->idtr = idtr;
vmss.vcpu_regs[cpu] |= REGS_PRESENT_IDTR;
} else {
@@ -266,6 +275,7 @@ vmware_vmss_init(char *filename, FILE *ofp)
(ulonglong)(blockpos + nbytes));
break;
}
+ DEBUG_PARSE_PRINT((ofp, "\n"));
}
} else {
union {
--
2.20.1
8:34 a.m.
New subject: [PATCH 3/3] Support core files with "unusual" layout
The netdump code not only gets used for netdump/diskdump files, but also
for kdump core files. These can also be generated with the 'vmss2core'
tool that'll produce a slightly different format that isn't as densely
packed as we expect it to be. In fact, the implicit assumption that the
ELF program headers directly follow the ELF header isn't always true for
these files, as they may contain a small padding area after the ELF
header -- which is totally conforming in regards to the ELF spec. This
padding in combination with the implicit assumption of densely packed
headers make us interpret the padding bytes as program headers which is
obviously wrong.
Support these kind of core files too by not blindly assuming the program
headers follow the ELF header but by looking at the program header
offset in the ELF header and use that instead. Add some guarding sanity
checks to decline operating on obviously malicious or broken core files.
To not needlessly make things too complicated, allow a "padding space" of
up to 128 bytes only.
Signed-off-by: Mathias Krause <minipli(a)grsecurity.net>
---
netdump.c | 86 ++++++++++++++++++++++++++++++++++++++-----------------
netdump.h | 2 ++
2 files changed, 61 insertions(+), 27 deletions(-)
diff --git a/netdump.c b/netdump.c
index 406416af36bf..0490bb52a8ed 100644
--- a/netdump.c
+++ b/netdump.c
@@ -132,7 +132,7 @@ is_netdump(char *file, ulong source_query)
}
}
- size = MIN_NETDUMP_ELF_HEADER_SIZE;
+ size = SAFE_NETDUMP_ELF_HEADER_SIZE;
if ((eheader = (char *)malloc(size)) == NULL) {
fprintf(stderr, "cannot malloc minimum ELF header buffer\n");
clean_exit(1);
@@ -219,8 +219,22 @@ is_netdump(char *file, ulong source_query)
source_query))
goto bailout;
- load32 = (Elf32_Phdr *)
- &eheader[sizeof(Elf32_Ehdr)+sizeof(Elf32_Phdr)];
+ if (elf32->e_phoff != sizeof(Elf32_Ehdr)) {
+ if (CRASHDEBUG(1))
+ error(WARNING, "%s: first PHdr not following "
+ "EHdr (PHdr offset = %u)", file,
+ elf32->e_phoff);
+ /* it's okay as long as we've read enough data */
+ if (elf32->e_phoff > size - 2 * sizeof(Elf32_Phdr)) {
+ error(WARNING, "%s: PHdr to far into file!\n",
+ file);
+ goto bailout;
+ }
+ }
+
+ /* skip the NOTE program header */
+ load32 = (Elf32_Phdr *)
+ &eheader[elf32->e_phoff+sizeof(Elf32_Phdr)];
if ((load32->p_offset & (MIN_PAGE_SIZE-1)) ||
(load32->p_align == 0))
@@ -291,8 +305,22 @@ is_netdump(char *file, ulong source_query)
source_query))
goto bailout;
- load64 = (Elf64_Phdr *)
- &eheader[sizeof(Elf64_Ehdr)+sizeof(Elf64_Phdr)];
+ if (elf64->e_phoff != sizeof(Elf64_Ehdr)) {
+ if (CRASHDEBUG(1))
+ error(WARNING, "%s: first PHdr not following "
+ "EHdr (PHdr offset = %u)", file,
+ elf64->e_phoff);
+ /* it's okay as long as we've read enough data */
+ if (elf64->e_phoff > size - 2 * sizeof(Elf64_Phdr)) {
+ error(WARNING, "%s: PHdr to far into file!\n",
+ file);
+ goto bailout;
+ }
+ }
+
+ /* skip the NOTE program header */
+ load64 = (Elf64_Phdr *)
+ &eheader[elf64->e_phoff+sizeof(Elf64_Phdr)];
if ((load64->p_offset & (MIN_PAGE_SIZE-1)) ||
(load64->p_align == 0))
@@ -353,9 +381,8 @@ is_netdump(char *file, ulong source_query)
clean_exit(1);
}
nd->notes32 = (Elf32_Phdr *)
- &nd->elf_header[sizeof(Elf32_Ehdr)];
- nd->load32 = (Elf32_Phdr *)
- &nd->elf_header[sizeof(Elf32_Ehdr)+sizeof(Elf32_Phdr)];
+ &nd->elf_header[nd->elf32->e_phoff];
+ nd->load32 = nd->notes32 + 1;
if (format == NETDUMP_ELF32)
nd->page_size = (uint)nd->load32->p_align;
dump_Elf32_Ehdr(nd->elf32);
@@ -392,9 +419,8 @@ is_netdump(char *file, ulong source_query)
clean_exit(1);
}
nd->notes64 = (Elf64_Phdr *)
- &nd->elf_header[sizeof(Elf64_Ehdr)];
- nd->load64 = (Elf64_Phdr *)
- &nd->elf_header[sizeof(Elf64_Ehdr)+sizeof(Elf64_Phdr)];
+ &nd->elf_header[nd->elf64->e_phoff];
+ nd->load64 = nd->notes64 + 1;
if (format == NETDUMP_ELF64)
nd->page_size = (uint)nd->load64->p_align;
dump_Elf64_Ehdr(nd->elf64);
@@ -469,8 +495,8 @@ resize_elf_header(int fd, char *file, char **eheader_ptr, char
**sect0_ptr,
case NETDUMP_ELF32:
case KDUMP_ELF32:
num_pt_load_segments = elf32->e_phnum - 1;
- header_size = sizeof(Elf32_Ehdr) + sizeof(Elf32_Phdr) +
- (sizeof(Elf32_Phdr) * num_pt_load_segments);
+ header_size = MAX(sizeof(Elf32_Ehdr), elf32->e_phoff) +
+ (sizeof(Elf32_Phdr) * (num_pt_load_segments + 1));
break;
case NETDUMP_ELF64:
@@ -513,8 +539,8 @@ resize_elf_header(int fd, char *file, char **eheader_ptr, char
**sect0_ptr,
} else
num_pt_load_segments = elf64->e_phnum - 1;
- header_size = sizeof(Elf64_Ehdr) + sizeof(Elf64_Phdr) +
- (sizeof(Elf64_Phdr) * num_pt_load_segments);
+ header_size = MAX(sizeof(Elf64_Ehdr), elf64->e_phoff) +
+ (sizeof(Elf64_Phdr) * (num_pt_load_segments + 1));
break;
}
@@ -544,7 +570,7 @@ resize_elf_header(int fd, char *file, char **eheader_ptr, char
**sect0_ptr,
{
case NETDUMP_ELF32:
case KDUMP_ELF32:
- load32 = (Elf32_Phdr *)&eheader[sizeof(Elf32_Ehdr)+sizeof(Elf32_Phdr)];
+ load32 = (Elf32_Phdr *)&eheader[elf32->e_phoff+sizeof(Elf32_Phdr)];
p_offset32 = load32->p_offset;
for (i = 0; i < num_pt_load_segments; i++, load32 += 1) {
if (load32->p_offset &&
@@ -556,7 +582,7 @@ resize_elf_header(int fd, char *file, char **eheader_ptr, char
**sect0_ptr,
case NETDUMP_ELF64:
case KDUMP_ELF64:
- load64 = (Elf64_Phdr *)&eheader[sizeof(Elf64_Ehdr)+sizeof(Elf64_Phdr)];
+ load64 = (Elf64_Phdr *)&eheader[elf64->e_phoff+sizeof(Elf64_Phdr)];
p_offset64 = load64->p_offset;
for (i = 0; i < num_pt_load_segments; i++, load64 += 1) {
if (load64->p_offset &&
@@ -4459,8 +4485,12 @@ proc_kcore_init_32(FILE *fp, int kcore_fd)
close(fd);
elf32 = (Elf32_Ehdr *)&eheader[0];
- notes32 = (Elf32_Phdr *)&eheader[sizeof(Elf32_Ehdr)];
- load32 = (Elf32_Phdr *)&eheader[sizeof(Elf32_Ehdr)+sizeof(Elf32_Phdr)];
+ if (elf32->e_phoff > sizeof(eheader) - 2 * sizeof(Elf32_Phdr)) {
+ error(INFO, "/proc/kcore: ELF program header offset too big!\n");
+ return FALSE;
+ }
+ notes32 = (Elf32_Phdr *)&eheader[elf32->e_phoff];
+ load32 = notes32 + 1;
pkd->segments = elf32->e_phnum - 1;
@@ -4479,9 +4509,8 @@ proc_kcore_init_32(FILE *fp, int kcore_fd)
}
BCOPY(&eheader[0], &pkd->elf_header[0], pkd->header_size);
- pkd->notes32 = (Elf32_Phdr *)&pkd->elf_header[sizeof(Elf32_Ehdr)];
- pkd->load32 = (Elf32_Phdr *)
- &pkd->elf_header[sizeof(Elf32_Ehdr)+sizeof(Elf32_Phdr)];
+ pkd->notes32 = (Elf32_Phdr *)&pkd->elf_header[elf32->e_phoff];
+ pkd->load32 = pkd->notes32 + 1;
pkd->flags |= KCORE_ELF32;
kcore_memory_dump(CRASHDEBUG(1) ? fp : pc->nullfp);
@@ -4529,8 +4558,12 @@ proc_kcore_init_64(FILE *fp, int kcore_fd)
close(fd);
elf64 = (Elf64_Ehdr *)&eheader[0];
- notes64 = (Elf64_Phdr *)&eheader[sizeof(Elf64_Ehdr)];
- load64 = (Elf64_Phdr *)&eheader[sizeof(Elf64_Ehdr)+sizeof(Elf64_Phdr)];
+ if (elf64->e_phoff > sizeof(eheader) - 2 * sizeof(Elf64_Phdr)) {
+ error(INFO, "/proc/kcore: ELF program header offset too big!\n");
+ return FALSE;
+ }
+ notes64 = (Elf64_Phdr *)&eheader[elf64->e_phoff];
+ load64 = notes64 + 1;
pkd->segments = elf64->e_phnum - 1;
@@ -4550,9 +4583,8 @@ proc_kcore_init_64(FILE *fp, int kcore_fd)
}
BCOPY(&eheader[0], &pkd->elf_header[0], pkd->header_size);
- pkd->notes64 = (Elf64_Phdr *)&pkd->elf_header[sizeof(Elf64_Ehdr)];
- pkd->load64 = (Elf64_Phdr *)
- &pkd->elf_header[sizeof(Elf64_Ehdr)+sizeof(Elf64_Phdr)];
+ pkd->notes64 = (Elf64_Phdr *)&pkd->elf_header[elf64->e_phoff];
+ pkd->load64 = pkd->notes64 + 1;
pkd->flags |= KCORE_ELF64;
kcore_memory_dump(CRASHDEBUG(1) ? fp : pc->nullfp);
diff --git a/netdump.h b/netdump.h
index 7fa04f7c3a0f..844279bc4a00 100644
--- a/netdump.h
+++ b/netdump.h
@@ -25,6 +25,8 @@
sizeof(Elf64_Ehdr)+sizeof(Elf64_Phdr)+sizeof(Elf64_Phdr)
#define MIN_NETDUMP_ELF_HEADER_SIZE \
MAX(MIN_NETDUMP_ELF32_HEADER_SIZE, MIN_NETDUMP_ELF64_HEADER_SIZE)
+#define SAFE_NETDUMP_ELF_HEADER_SIZE \
+ (MIN_NETDUMP_ELF_HEADER_SIZE+128)
#define NT_TASKSTRUCT 4
#define NT_DISKDUMP 0x70000001
--
2.20.1
2:38 a.m.
Hi Mathias,
Cc Bhupesh, Lianbo,
I'm on vacation and will review the patches when I get back next week.
Thanks,
Kazu
On Thu, Jul 30, 2020 at 10:35 PM Mathias Krause <minipli(a)grsecurity.net> wrote:
[Resend as the original posting apaprnetly got stuck in the mail queue.]
This small patch series enhances support for VMware vmss dump and core
files by fixing some bugs I ran into.
I meanwhile realized that the register dump of patch 2 can also be seen
via 'help -r' but its formating fixes are useful nonetheless.
Please apply!
Thanks,
Mathias
Mathias Krause (3):
vmware: vmss - support huge holes in vmem
vmware: vmss - beautify and extend debug log
Support core files with "unusual" layout
netdump.c | 86 +++++++++++++++++++++++++++++++++++----------------
netdump.h | 2 ++
vmware_vmss.c | 18 +++++++++--
3 files changed, 76 insertions(+), 30 deletions(-)
--
2.20.1
--
Crash-utility mailing list
Crash-utility(a)redhat.com
https://www.redhat.com/mailman/listinfo/crash-utility
6:25 a.m.
在 2020年08月03日 15:38, Kazuhito Hagio 写道:
Hi Mathias,
Cc Bhupesh, Lianbo,
I'm on vacation and will review the patches when I get back next week.
Wish you have a nice vacation! :-)
Thanks.
Lianbo
Thanks,
Kazu
On Thu, Jul 30, 2020 at 10:35 PM Mathias Krause <minipli(a)grsecurity.net> wrote:
>
> [Resend as the original posting apaprnetly got stuck in the mail queue.]
>
> This small patch series enhances support for VMware vmss dump and core
> files by fixing some bugs I ran into.
>
> I meanwhile realized that the register dump of patch 2 can also be seen
> via 'help -r' but its formating fixes are useful nonetheless.
>
> Please apply!
>
> Thanks,
> Mathias
>
> Mathias Krause (3):
> vmware: vmss - support huge holes in vmem
> vmware: vmss - beautify and extend debug log
> Support core files with "unusual" layout
>
> netdump.c | 86 +++++++++++++++++++++++++++++++++++----------------
> netdump.h | 2 ++
> vmware_vmss.c | 18 +++++++++--
> 3 files changed, 76 insertions(+), 30 deletions(-)
>
> --
> 2.20.1
>
>
> --
> Crash-utility mailing list
> Crash-utility(a)redhat.com
> https://www.redhat.com/mailman/listinfo/crash-utility
>
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5 comments
3 participants
participants (3)
-
Kazuhito Hagio -
lijiang -
Mathias Krause