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Kernel: Add missing iovec base validation for writev() syscall

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We were forgetting to validate the base pointers of iovecs passed into
the writev() syscall.

Thanks to braindead for finding this bug! :^)
This commit is contained in:
Andreas Kling 2020-01-05 10:16:19 +01:00
parent c89fe8a6a3
commit 1525c11928
1 changed files with 10 additions and 3 deletions
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13
Kernel/Process.cpp
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@ -1282,8 +1282,15 @@ ssize_t Process::sys$writev(int fd, const struct iovec* iov, int iov_count)
return -EFAULT;
u64 total_length = 0;
Vector<iovec, 32> vecs;
vecs.ensure_capacity(iov_count);
for (int i = 0; i < iov_count; ++i) {
total_length += iov[i].iov_len;
void* base = iov[i].iov_base;
size_t len = iov[i].iov_len;
if (!validate_read(base, len))
return -EFAULT;
vecs.append({ base, len });
total_length += len;
if (total_length > INT32_MAX)
return -EINVAL;
}
@ -1296,8 +1303,8 @@ ssize_t Process::sys$writev(int fd, const struct iovec* iov, int iov_count)
return -EBADF;
int nwritten = 0;
for (int i = 0; i < iov_count; ++i) {
int rc = do_write(*description, (const u8*)iov[i].iov_base, iov[i].iov_len);
for (auto& vec : vecs) {
int rc = do_write(*description, (const u8*)vec.iov_base, vec.iov_len);
if (rc < 0) {
if (nwritten == 0)
return rc;