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Fix unaligned syscall arg loads on mipsel #69

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Merged
lacraig2 merged 1 commit into from
May 19, 2026
Merged

Fix unaligned syscall arg loads on mipsel #69

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21 changes: 7 additions & 14 deletions src/hooks/syscalls_hc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -192,14 +192,7 @@ static inline void fill_handler(struct syscall_event *args, int argc, const unsi
// Copy arguments safely - add proper NULL checks before dereferencing
for (i = 0; i < IGLOO_SYSCALL_MAXARGS; i++){
if (i < argc && args_ptrs && args_ptrs[i]) {
// Safely copy argument value - verify valid pointer first
unsigned long arg_ptr = args_ptrs[i];
if (arg_ptr && !IS_ERR_VALUE(arg_ptr)) {
args->args[i] = *(unsigned long*)arg_ptr;
} else {
args->args[i] = 0;
DBG_PRINTK("IGLOO: Invalid argument pointer at index %d\n", i);
}
args->args[i] = igloo_syscall_arg_value(args_ptrs, i);
} else {
args->args[i] = 0; // Initialize unused args to 0
}
Expand Down Expand Up @@ -323,7 +316,7 @@ static inline bool hook_matches_syscall(struct kernel_syscall_hook *hook,
if (argc > 0) {
struct value_filter *f = &hook->hook.arg_filters[0];
if (f->enabled) {
long arg_val = *(long *)args[0];
long arg_val = (long)igloo_syscall_arg_value(args, 0);
if (f->type == SYSCALLS_HC_FILTER_EXACT) {
if (arg_val != f->value) return false;
} else {
Expand All @@ -334,7 +327,7 @@ static inline bool hook_matches_syscall(struct kernel_syscall_hook *hook,
if (argc > 1) {
struct value_filter *f = &hook->hook.arg_filters[1];
if (f->enabled) {
long arg_val = *(long *)args[1];
long arg_val = (long)igloo_syscall_arg_value(args, 1);
if (f->type == SYSCALLS_HC_FILTER_EXACT) {
if (arg_val != f->value) return false;
} else {
Expand All @@ -345,7 +338,7 @@ static inline bool hook_matches_syscall(struct kernel_syscall_hook *hook,
if (argc > 2) {
struct value_filter *f = &hook->hook.arg_filters[2];
if (f->enabled) {
long arg_val = *(long *)args[2];
long arg_val = (long)igloo_syscall_arg_value(args, 2);
if (f->type == SYSCALLS_HC_FILTER_EXACT) {
if (arg_val != f->value) return false;
} else {
Expand All @@ -356,7 +349,7 @@ static inline bool hook_matches_syscall(struct kernel_syscall_hook *hook,
if (argc > 3) {
struct value_filter *f = &hook->hook.arg_filters[3];
if (f->enabled) {
long arg_val = *(long *)args[3];
long arg_val = (long)igloo_syscall_arg_value(args, 3);
if (f->type == SYSCALLS_HC_FILTER_EXACT) {
if (arg_val != f->value) return false;
} else {
Expand All @@ -367,7 +360,7 @@ static inline bool hook_matches_syscall(struct kernel_syscall_hook *hook,
if (argc > 4) {
struct value_filter *f = &hook->hook.arg_filters[4];
if (f->enabled) {
long arg_val = *(long *)args[4];
long arg_val = (long)igloo_syscall_arg_value(args, 4);
if (f->type == SYSCALLS_HC_FILTER_EXACT) {
if (arg_val != f->value) return false;
} else {
Expand All @@ -378,7 +371,7 @@ static inline bool hook_matches_syscall(struct kernel_syscall_hook *hook,
if (argc > 5) {
struct value_filter *f = &hook->hook.arg_filters[5];
if (f->enabled) {
long arg_val = *(long *)args[5];
long arg_val = (long)igloo_syscall_arg_value(args, 5);
if (f->type == SYSCALLS_HC_FILTER_EXACT) {
if (arg_val != f->value) return false;
} else {
Expand Down
25 changes: 25 additions & 0 deletions src/hooks/syscalls_hc.h
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,14 @@
#include <linux/spinlock.h>
#include <linux/hashtable.h>
#include <linux/uaccess.h>
#include <linux/err.h>
#include <linux/version.h>

#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 13, 0)
#include <linux/unaligned.h>
#else
#include <asm/unaligned.h>
#endif

#include "igloo_syscall_macros.h"

Expand Down Expand Up @@ -100,6 +108,23 @@ bool portalcall_fastpath_should_skip(bool is_sendto,
int argc,
const unsigned long args[]);

static inline unsigned long igloo_syscall_arg_value(const unsigned long args[],
int index)
{
unsigned long arg_slot;

if (!args || index < 0 || index >= IGLOO_SYSCALL_MAXARGS) {
return 0;
}

arg_slot = args[index];
if (!arg_slot || IS_ERR_VALUE(arg_slot)) {
return 0;
}

return get_unaligned((unsigned long *)arg_slot);
}

/* Unregister a syscall hook using its pointer */
int unregister_syscall_hook(struct kernel_syscall_hook *hook_ptr);

Expand Down
4 changes: 2 additions & 2 deletions src/portal/portalcall_fastpath.c
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Original file line number Diff line number Diff line change
Expand Up @@ -81,12 +81,12 @@ bool portalcall_fastpath_should_skip(bool is_sendto,
return false;
}

magic = *(unsigned long *)args[0];
magic = igloo_syscall_arg_value(args, 0);
if ((magic & 0xffffffffUL) != PORTALCALL_SYSCALL_MAGIC) {
return false;
}

user_magic = *(unsigned long *)args[1];
user_magic = igloo_syscall_arg_value(args, 1);
return !portalcall_magic_is_registered((u32)user_magic);
}
EXPORT_SYMBOL(portalcall_fastpath_should_skip);
Expand Down
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