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Fix reading info permission deny bugs.
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Details:
    1. Change default /dev/mem to sysfs tables, if /dev/mem is unavailable, use sysfs tables instead.
    2. Modify init method from dmidecodemodule.
    3. Add read_file function instead memchunk.
    4. Add SM3 reading function and get version function.
    5. Test physical machine and KVM machine

Resolves: #39
Signed-off-by: Huzz <[email protected]>
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@HuO50 @lian-bo
HuO50 authored and lian-bo committed Sep 4, 2022
1 parent f0a089a commit aef6454
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Showing 8 changed files with 703 additions and 246 deletions.
117 changes: 89 additions & 28 deletions src/dmidecode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5197,7 +5197,7 @@ dmi_codes_major *find_dmiMajor(const struct dmi_header *h)
return NULL;
}

static void dmi_table(Log_t *logp, int type, u32 base, u16 len, u16 num, u16 ver, const char *devmem, xmlNode *xmlnode)
static void dmi_table(Log_t *logp, int type, u32 base, u16 len, u16 num, u16 ver, const char *devmem, u32 flags, xmlNode *xmlnode)
{
static u8 version_added = 0;
u8 *buf;
Expand All @@ -5221,35 +5221,40 @@ static void dmi_table(Log_t *logp, int type, u32 base, u16 len, u16 num, u16 ver
info_n = NULL;
}

if((buf = mem_chunk(logp, base, len, devmem)) == NULL) {
log_append(logp, LOGFL_NODUPS, LOG_WARNING, "Table is unreachable, sorry."
#ifndef USE_MMAP
"Try compiling dmidecode with -DUSE_MMAP."
#endif
);
return;
}
if(flags & FLAG_NO_FILE_OFFSET){
/*
* When reading from sysfs or from a dump file, the file may be
* shorter than announced. For SMBIOS v3 this is expcted, as we
* only know the maximum table size, not the actual table size.
* For older implementations (and for SMBIOS v3 too), this
* would be the result of the kernel truncating the table on
* parse error.
*/
size_t size = len;
buf = read_file(logp, flags & FLAG_NO_FILE_OFFSET ? 0 : base, &size, devmem);
if (num && size != (size_t)len){
log_append(logp, LOGFL_NODUPS, LOG_WARNING, "Wrong DMI structures length: %i bytes announced, only %lu bytes available.\n", len, (unsigned long)size );
}
len = size;
} else {
buf = mem_chunk(logp, base, len, devmem);
}

if (ver > SUPPORTED_SMBIOS_VER){
log_append(logp, LOGFL_NODUPS, LOG_WARNING, "# SMBIOS implementations newer than version %u.%u are not\n", "# fully supported by this version of dmidecode.\n", SUPPORTED_SMBIOS_VER >> 8, SUPPORTED_SMBIOS_VER & 0xFF);
}

if (ver > SUPPORTED_SMBIOS_VER) {
log_append(logp, LOGFL_NODUPS, LOG_WARNING,
"# SMBIOS implementations newer than version %u.%u are not\n"
"# fully supported by this version of dmidecode.\n",
SUPPORTED_SMBIOS_VER >> 8, SUPPORTED_SMBIOS_VER & 0xFF);
}
// FIXME: This is hackerish ... rather try to avoid looping dmi_table() calls too much
if( version_added == 0 ) {
dmixml_AddAttribute(xmlnode, "smbios_version", "%u.%u", ver >> 8, ver & 0xFF);
version_added = 1;
}

data = buf;
while(i < num && data + 4 <= buf + len) { /* 4 is the length of an SMBIOS structure header */

data = buf;
while(i < num && data + 4 <= buf + len) { /* 4 is the length of an SMBIOS structure header */
u8 *next;
struct dmi_header h;

to_dmi_header(&h, data);

/*
** If a short entry is found (less than 4 bytes), not only it
** is invalid, but we cannot reliably locate the next entry.
Expand All @@ -5258,8 +5263,8 @@ static void dmi_table(Log_t *logp, int type, u32 base, u16 len, u16 num, u16 ver
*/
if(h.length < 4) {
log_append(logp, LOGFL_NORMAL, LOG_WARNING,
"Invalid entry length (%i) for type %i. DMI table is broken! Stop.",
(unsigned int)h.length, type);
"Invalid entry length (%i) for type %i. DMI table is broken! Stop.",
(unsigned int)h.length, type);
break;
}

Expand All @@ -5278,7 +5283,6 @@ static void dmi_table(Log_t *logp, int type, u32 base, u16 len, u16 num, u16 ver
next++;
}
next += 2;

xmlNode *handle_n = NULL;
if( h.type == type ) {
if(next - buf <= len) {
Expand Down Expand Up @@ -5309,6 +5313,7 @@ static void dmi_table(Log_t *logp, int type, u32 base, u16 len, u16 num, u16 ver
dmixml_AddAttribute(handle_n, "length", "%i", (next - buf));
dmixml_AddAttribute(handle_n, "expected_length", "%i", len);


log_append(logp, LOGFL_NODUPS, LOG_WARNING,
"DMI/SMBIOS type 0x%02X is exceeding the expected buffer "
"size by %i bytes. Will not decode this entry.",
Expand Down Expand Up @@ -5344,6 +5349,60 @@ static void dmi_table(Log_t *logp, int type, u32 base, u16 len, u16 num, u16 ver
free(buf);
}

int _smbios3_decode_check(u8 *buf){
int check = (!checksum(buf, buf[0x06])) ? 0 : 1;
return check;
}

xmlNode *smbios3_decode_get_version(u8 * buf, const char *devmem)
{
int check = _smbios3_decode_check(buf);

xmlNode *data_n = xmlNewNode(NULL, (xmlChar *) "DMIversion");
assert( data_n != NULL );

dmixml_AddAttribute(data_n, "type", "SMBIOS");

if(check == 1) {
u16 ver = (buf[0x07] << 16) + (buf[0x08] << 8) + buf[0x09];

dmixml_AddTextContent(data_n, "SMBIOS %i.%i.%i present", buf[0x07], buf[0x08], buf[0x09]);
dmixml_AddAttribute(data_n, "version", "%i.%i.%i", buf[0x07], buf[0x08],buf[0x09]);
} else if(check == 0) {
dmixml_AddTextContent(data_n, "No SMBIOS nor DMI entry point found");
dmixml_AddAttribute(data_n, "unknown", "1");
}
return data_n;
}

int smbios3_decode(Log_t *logp, int type, u8 *buf, const char *devmem, u32 flags, xmlNode *xmlnode)
{
u32 ver;
u64 offset;

/* Don't let checksum run beyond the buffer */
if (buf[0x06] > 0x20)
{
return 0;
}

int check = _smbios3_decode_check(buf);
if (check == 1)
{
ver = (buf[0x07] << 16) + (buf[0x08] << 8) + buf[0x09];
offset = QWORD(buf + 0x10);

if (!(flags & FLAG_NO_FILE_OFFSET) && offset.h && sizeof(off_t) < 8)
{
return 0;
}

dmi_table(logp, type, ((off_t)offset.h << 32) | offset.l, DWORD(buf+0x0C), 0, ver, devmem, flags | FLAG_STOP_AT_EOT, xmlnode);
}

return check;
}

int _smbios_decode_check(u8 * buf)
{
int check = (!checksum(buf, buf[0x05]) || memcmp(buf + 0x10, "_DMI_", 5) != 0 ||
Expand All @@ -5370,7 +5429,8 @@ xmlNode *smbios_decode_get_version(u8 * buf, const char *devmem)
_M = 0;
switch (ver) {
case 0x021F:
_m = 31;
case 0x0221:
_m = ver & 0xFF;
_M = 3;
ver = 0x0203;
break;
Expand All @@ -5396,7 +5456,7 @@ xmlNode *smbios_decode_get_version(u8 * buf, const char *devmem)
return data_n;
}

int smbios_decode(Log_t *logp, int type, u8 *buf, const char *devmem, xmlNode *xmlnode)
int smbios_decode(Log_t *logp, int type, u8 *buf, const char *devmem, u32 flags, xmlNode *xmlnode)
{
int check = _smbios_decode_check(buf);

Expand All @@ -5405,6 +5465,7 @@ int smbios_decode(Log_t *logp, int type, u8 *buf, const char *devmem, xmlNode *x

switch (ver) {
case 0x021F:
case 0x0221:
ver = 0x0203;
break;
case 0x0233:
Expand All @@ -5413,7 +5474,7 @@ int smbios_decode(Log_t *logp, int type, u8 *buf, const char *devmem, xmlNode *x
}
// printf(">>%d @ %d, %d<<\n", DWORD(buf+0x18), WORD(buf+0x16), WORD(buf+0x1C));
dmi_table(logp, type, DWORD(buf + 0x18), WORD(buf + 0x16), WORD(buf + 0x1C), ver, devmem,
xmlnode);
flags, xmlnode);
}
return check;
}
Expand Down Expand Up @@ -5451,13 +5512,13 @@ xmlNode *legacy_decode_get_version(u8 * buf, const char *devmem)
return data_n;
}

int legacy_decode(Log_t *logp, int type, u8 *buf, const char *devmem, xmlNode *xmlnode)
int legacy_decode(Log_t *logp, int type, u8 *buf, const char *devmem, u32 flags, xmlNode *xmlnode)
{
int check = _legacy_decode_check(buf);

if(check == 1)
dmi_table(logp, type, DWORD(buf + 0x08), WORD(buf + 0x06), WORD(buf + 0x0C),
((buf[0x0E] & 0xF0) << 4) + (buf[0x0E] & 0x0F), devmem, xmlnode);
((buf[0x0E] & 0xF0) << 4) + (buf[0x0E] & 0x0F), devmem, flags, xmlnode);
return check;
}

13 changes: 11 additions & 2 deletions src/dmidecode.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,13 @@
#include "dmihelper.h"
#include "dmierror.h"

#define FLAG_NO_FILE_OFFSET (1 << 0)
#define FLAG_STOP_AT_EOT (1 << 1)

#define SYS_FIRMWARE_DIR "/sys/firmware/dmi/tables"
#define SYS_ENTRY_FILE SYS_FIRMWARE_DIR "/smbios_entry_point"
#define SYS_TABLE_FILE SYS_FIRMWARE_DIR "/DMI"

struct dmi_header {
u8 type;
u8 length;
Expand All @@ -34,10 +41,12 @@ void dmi_dump(xmlNode *node, struct dmi_header * h);
xmlNode *dmi_decode(xmlNode *parent_n, dmi_codes_major *dmiMajor, struct dmi_header * h, u16 ver);
void to_dmi_header(struct dmi_header *h, u8 * data);

xmlNode *smbios3_decode_get_version(u8 * buf, const char *devmem);
xmlNode *smbios_decode_get_version(u8 * buf, const char *devmem);
xmlNode *legacy_decode_get_version(u8 * buf, const char *devmem);
int smbios_decode(Log_t *logp, int type, u8 *buf, const char *devmem, xmlNode *xmlnode);
int legacy_decode(Log_t *logp, int type, u8 *buf, const char *devmem, xmlNode *xmlnode);
int smbios3_decode(Log_t *logp, int type, u8 *buf, const char *devmem, u32 flags, xmlNode *xmlnode);
int smbios_decode(Log_t *logp, int type, u8 *buf, const char *devmem, u32 flags, xmlNode *xmlnode);
int legacy_decode(Log_t *logp, int type, u8 *buf, const char *devmem, u32 flags, xmlNode *xmlnode);

const char *dmi_string(const struct dmi_header *dm, u8 s);
void dmi_system_uuid(xmlNode *node, const u8 * p, u16 ver);
Expand Down
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