crtxcr
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exile.h
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Use overflow-safe operator builtins 

As a precaution as it does not hurt
This commit is contained in:
Albert S. 2021-09-12 19:41:07 +02:00
parent 215032f32c
commit 8bc0d1e73a
1 changed files with 21 additions and 3 deletions
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24
qssb.h
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@ -250,8 +250,8 @@ static int qssb_entry_append(struct qssb_allocated_entry *entry, void *data, siz
if(remaining < bytes)
{
size_t expandval = QSSB_ENTRY_ALLOC_SIZE > bytes ? QSSB_ENTRY_ALLOC_SIZE : bytes;
size_t sizenew = entry->size + expandval;
if(sizenew < entry->size)
size_t sizenew = 0;
if(__builtin_add_overflow(entry->size, expandval, &sizenew))
{
QSSB_LOG_ERROR("overflow in qssb_entry_append\n");
return -EINVAL;
@ -273,7 +273,13 @@ static int qssb_entry_append(struct qssb_allocated_entry *entry, void *data, siz
static int qssb_append_syscall(struct qssb_allocated_entry *entry, long *syscalls, size_t n)
{
return qssb_entry_append(entry, syscalls, n * sizeof(long));
size_t bytes = 0;
if(__builtin_mul_overflow(n, sizeof(long), &bytes))
{
QSSB_LOG_ERROR("Overflow while trying to add system calls\n");
return -EINVAL;
}
return qssb_entry_append(entry, syscalls, bytes);
}
static int is_valid_syscall_policy(unsigned int policy)
@ -749,6 +755,18 @@ static int qssb_enable_syscall_policy(struct qssb_policy *policy)
long *syscalls = NULL;
size_t n = 0;
get_syscall_array(current_policy, &syscalls, &n);
unsigned short int newsize;
if(__builtin_add_overflow(current_filter_index, n, &newsize))
{
QSSB_LOG_ERROR("Overflow when trying to add new system calls\n");
return -EINVAL;
}
if(newsize > (sizeof(filter)/sizeof(filter[0]))-1)
{
QSSB_LOG_ERROR("Too many system calls added\n");
return -EINVAL;
}
append_syscalls_to_bpf(syscalls, n, current_policy->policy, filter, &current_filter_index);
current_policy = current_policy->next;
}