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Improve save_args_to_submit_buf #4217

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Aug 14, 2024
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Improve save_args_to_submit_buf #4217

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180 changes: 97 additions & 83 deletions pkg/ebpf/c/common/buffer.h
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Original file line number Diff line number Diff line change
Expand Up @@ -339,102 +339,116 @@ statfunc int save_sockaddr_to_buf(args_buffer_t *buf, struct socket *sock, u8 in

#define DEC_ARG(n, enc_arg) ((enc_arg >> (8 * n)) & 0xFF)

#define BITMASK_INDIRECT_VALUE_TYPES \
((u64) 1 << STR_T | (u64) 1 << SOCKADDR_T | (u64) 1 << INT_ARR_2_T | (u64) 1 << TIMESPEC_T)

#define BITMASK_COMMON_TYPES \
((u64) 1 << INT_T | (u64) 1 << UINT_T | (u64) 1 << LONG_T | (u64) 1 << ULONG_T | \
(u64) 1 << OFF_T_T | (u64) 1 << MODE_T_T | (u64) 1 << DEV_T_T | (u64) 1 << SIZE_T_T | \
(u64) 1 << POINTER_T | (u64) 1 << STR_ARR_T | (u64) 1 << BYTES_T | (u64) 1 << U16_T | \
(u64) 1 << CRED_T | (u64) 1 << UINT64_ARR_T | (u64) 1 << U8_T)

#define ARG_TYPE_MAX_ARRAY (u8) TIMESPEC_T // last element defined in argument_type_e
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// Ensure that only values that can be held by an u8 are assigned to sizes.
// If the size is greater than 255, assign 0 (making it evident) and handle it as a special case.
static u8 type_size_table[ARG_TYPE_MAX_ARRAY + 1] = {
[NONE_T] = 0,
[INT_T] = sizeof(int),
[UINT_T] = sizeof(unsigned int),
[LONG_T] = sizeof(long),
[ULONG_T] = sizeof(unsigned long),
[OFF_T_T] = sizeof(off_t),
[MODE_T_T] = sizeof(mode_t),
[DEV_T_T] = sizeof(dev_t),
[SIZE_T_T] = sizeof(size_t),
[POINTER_T] = sizeof(void *),
[STR_T] = 0,
[STR_ARR_T] = 0,
[SOCKADDR_T] = sizeof(short),
[BYTES_T] = 0,
[U16_T] = sizeof(u16),
[CRED_T] = sizeof(struct cred),
[INT_ARR_2_T] = sizeof(int[2]),
[UINT64_ARR_T] = 0,
[U8_T] = sizeof(u8),
[TIMESPEC_T] = 0,
};

statfunc int save_args_to_submit_buf(event_data_t *event, args_t *args)
{
unsigned int i;
unsigned int rc = 0;
unsigned int arg_num = 0;
short family = 0;

if (event->config.param_types == 0)
u8 i;
u8 type;
u64 type_mask;
u32 rc = 0;
u32 arg_num = 0;
u32 size;
void *arg;
short family;

if (unlikely(event->config.param_types == 0))
return 0;

#pragma unroll
for (i = 0; i < 6; i++) {
int size = 0;
u8 type = DEC_ARG(i, event->config.param_types);
u8 index = i;
type = DEC_ARG(i, event->config.param_types);

// bounds check for the verifier
if (unlikely(type >= ARG_TYPE_MAX_ARRAY))
continue; // skip types not defined in the type_size_table
size = type_size_table[type];

if (type == NONE_T)
continue;
type_mask = (u64) 1 << type; // type value must be < 64

if (BITMASK_INDIRECT_VALUE_TYPES & type_mask)
arg = (void *) args->args[i];
else
arg = (void *) &args->args[i];

// handle common types
if (BITMASK_COMMON_TYPES & type_mask)
goto save_arg;

// handle special types
switch (type) {
case NONE_T:
break;
case INT_T:
size = sizeof(int);
break;
case UINT_T:
size = sizeof(unsigned int);
break;
case OFF_T_T:
size = sizeof(off_t);
break;
case DEV_T_T:
size = sizeof(dev_t);
break;
case MODE_T_T:
size = sizeof(mode_t);
break;
case LONG_T:
size = sizeof(long);
break;
case ULONG_T:
size = sizeof(unsigned long);
break;
case SIZE_T_T:
size = sizeof(size_t);
break;
case POINTER_T:
size = sizeof(void *);
break;
case U8_T:
size = sizeof(u8);
break;
case U16_T:
size = sizeof(u16);
break;
case STR_T:
rc = save_str_to_buf(&(event->args_buf), (void *) args->args[i], index);
break;
case SOCKADDR_T:
if (args->args[i]) {
bpf_probe_read(&family, sizeof(short), (void *) args->args[i]);
switch (family) {
case AF_UNIX:
size = bpf_core_type_size(struct sockaddr_un);
break;
case AF_INET:
size = bpf_core_type_size(struct sockaddr_in);
break;
case AF_INET6:
size = bpf_core_type_size(struct sockaddr_in6);
break;
default:
size = sizeof(short);
}
rc = save_to_submit_buf(
&(event->args_buf), (void *) (args->args[i]), size, index);
} else {
rc = save_to_submit_buf(&(event->args_buf), &family, sizeof(short), index);
rc = save_str_to_buf(&(event->args_buf), arg, i);
goto check_rc;
case SOCKADDR_T: {
// default size from the type_size_table
if (!arg) {
family = 0;
arg = (void *) &family;
goto save_arg;
}
break;
case INT_ARR_2_T:
size = sizeof(int[2]);
rc = save_to_submit_buf(&(event->args_buf), (void *) (args->args[i]), size, index);
break;

bpf_probe_read(&family, sizeof(short), arg);
switch (family) {
case AF_UNIX:
size = bpf_core_type_size(struct sockaddr_un);
break;
case AF_INET:
size = bpf_core_type_size(struct sockaddr_in);
break;
case AF_INET6:
size = bpf_core_type_size(struct sockaddr_in6);
break;
}
goto save_arg;
}
case TIMESPEC_T:
size = bpf_core_type_size(struct __kernel_timespec);
rc = save_to_submit_buf(&(event->args_buf), (void *) (args->args[i]), size, index);
break;
}
switch (type) {
case NONE_T:
case STR_T:
case SOCKADDR_T:
case INT_ARR_2_T:
case TIMESPEC_T:
break;
goto save_arg;
default:
rc = save_to_submit_buf(&(event->args_buf), (void *) &(args->args[i]), size, index);
break;
goto save_arg;
}

save_arg:
rc = save_to_submit_buf(&(event->args_buf), arg, size, i);

check_rc:
if (rc > 0) {
arg_num++;
rc = 0;
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2 changes: 2 additions & 0 deletions pkg/ebpf/c/types.h
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Original file line number Diff line number Diff line change
Expand Up @@ -153,6 +153,8 @@ typedef struct args {
unsigned long args[6];
} args_t;

// NOTE: If any fields are added to argument_type_e, the array type_size_table
// (and related defines) must be updated accordingly.
enum argument_type_e
{
NONE_T = 0UL,
Expand Down
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