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authorSamuel Thibault <samuel.thibault@ens-lyon.org>2020-11-23 00:31:41 +0000
committerSamuel Thibault <samuel.thibault@ens-lyon.org>2020-11-23 00:31:41 +0000
commit76ea70c613cee23a1846b9605e6433c1fa8baea7 (patch)
tree6349d53cee3cf6febcbf9bb26c5878e201d643f5 /hurd
parentdba88fb3ed3e70d2ad797f447a2a894b0891a5d7 (diff)
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hurd report-wait: Fix stpcpy usage
We shall not overflow the size of the description parameter. This makes describe_number and describe_port behave like strpcpy (except for not filling all the end of buffer with zeroes) and _S_msg_report_wait use series of stpncpy-like call. If we were to overflow, we can now detect it and return ENOMEM.
Diffstat (limited to 'hurd')
-rw-r--r--hurd/report-wait.c78
1 files changed, 49 insertions, 29 deletions
diff --git a/hurd/report-wait.c b/hurd/report-wait.c
index eba43c9..2910321 100644
--- a/hurd/report-wait.c
+++ b/hurd/report-wait.c
@@ -26,12 +26,16 @@
#include <intr-msg.h>
static char *
-describe_number (string_t description, const char *flavor, long int i)
+describe_number (char *description, const char *flavor, long int i, size_t size)
{
unsigned long int j;
- char *p = flavor == NULL ? description : __stpcpy (description, flavor);
+ char *limit = description + size;
+ char *p = flavor == NULL ? description : __stpncpy (description, flavor, size);
char *end;
+ if (p == limit)
+ return p;
+
/* Handle sign. */
if (i < 0)
{
@@ -39,15 +43,24 @@ describe_number (string_t description, const char *flavor, long int i)
*p++ = '-';
}
+ if (p == limit)
+ return p;
+
/* Allocate space for the number at the end of DESCRIPTION. */
for (j = i; j >= 10; j /= 10)
p++;
end = p + 1;
- *end = '\0';
+
+ if (end < limit)
+ *end = '\0';
+ else
+ end = limit;
do
{
- *p-- = '0' + i % 10;
+ if (p < limit)
+ *p = '0' + i % 10;
+ p--;
i /= 10;
} while (i != 0);
@@ -55,27 +68,27 @@ describe_number (string_t description, const char *flavor, long int i)
}
static char *
-describe_port (string_t description, mach_port_t port)
+describe_port (char *description, mach_port_t port, size_t size)
{
int i;
if (port == MACH_PORT_NULL)
- return __stpcpy (description, "(null)");
+ return __stpncpy (description, "(null)", size);
if (port == MACH_PORT_DEAD)
- return __stpcpy (description, "(dead)");
+ return __stpncpy (description, "(dead)", size);
if (port == __mach_task_self ())
- return __stpcpy (description, "task-self");
+ return __stpncpy (description, "task-self", size);
for (i = 0; i < _hurd_nports; ++i)
if (port == _hurd_ports[i].port)
- return describe_number (description, "init#", i);
+ return describe_number (description, "init#", i, size);
if (_hurd_init_dtable)
{
for (i = 0; i < _hurd_init_dtablesize; ++i)
if (port == _hurd_init_dtable[i])
- return describe_number (description, "fd#", i);
+ return describe_number (description, "fd#", i, size);
}
if (_hurd_dtable)
{
@@ -83,12 +96,12 @@ describe_port (string_t description, mach_port_t port)
if (_hurd_dtable[i] == NULL)
continue;
else if (port == _hurd_dtable[i]->port.port)
- return describe_number (description, "fd#", i);
+ return describe_number (description, "fd#", i, size);
else if (port == _hurd_dtable[i]->ctty.port)
- return describe_number (description, "bgfd#", i);
+ return describe_number (description, "bgfd#", i, size);
}
- return describe_number (description, "port#", port);
+ return describe_number (description, "port#", port, size);
}
@@ -106,13 +119,15 @@ kern_return_t
_S_msg_report_wait (mach_port_t msgport, thread_t thread,
string_t description, mach_msg_id_t *msgid)
{
+ char *limit = description + 1024; /* XXX */
+ char *cur = description;
*msgid = 0;
if (thread == _hurd_msgport_thread)
/* Cute. */
- strcpy (description, "msgport");
+ cur = __stpncpy (cur, "msgport", limit - cur);
else if (&_hurd_itimer_thread && thread == _hurd_itimer_thread)
- strcpy (description, "itimer");
+ cur = __stpncpy (cur, "itimer", limit - cur);
else
{
/* Make sure this is really one of our threads. */
@@ -129,7 +144,7 @@ _S_msg_report_wait (mach_port_t msgport, thread_t thread,
return EINVAL;
if (ss->suspended != MACH_PORT_NULL)
- strcpy (description, "sigsuspend");
+ cur = __stpncpy (cur, "sigsuspend", limit - cur);
else
{
/* Examine the thread's state to see if it is blocked in an RPC. */
@@ -155,7 +170,6 @@ _S_msg_report_wait (mach_port_t msgport, thread_t thread,
&& MSG_EXAMINE (&state, msgid, &rcv_port, &send_port,
&option, &timeout) == 0)
{
- char *p;
if (send_port != MACH_PORT_NULL && *msgid != 0)
{
/* For the normal case of RPCs, we consider the
@@ -168,13 +182,14 @@ _S_msg_report_wait (mach_port_t msgport, thread_t thread,
/* This is a Hurd interruptible RPC.
Mark it by surrounding the port description
string with [...] brackets. */
- description[0] = '[';
- p = describe_port (description + 1, send_port);
- *p++ = ']';
- *p = '\0';
+ if (cur < limit)
+ *cur++ = '[';
+ cur = describe_port (cur, send_port, limit - cur);
+ if (cur < limit)
+ *cur++ = ']';
}
else
- (void) describe_port (description, send_port);
+ cur = describe_port (cur, send_port, limit - cur);
}
else if (rcv_port != MACH_PORT_NULL)
{
@@ -183,7 +198,8 @@ _S_msg_report_wait (mach_port_t msgport, thread_t thread,
some garbage or perhaps the msgid of the last
message this thread received, but it's not a
helpful thing to return. */
- strcpy (describe_port (description, rcv_port), ":rcv");
+ cur = describe_port (cur, rcv_port, limit - cur);
+ cur = __stpncpy (cur, ":rcv", limit - cur);
*msgid = 0;
}
else if ((option & (MACH_RCV_MSG|MACH_RCV_TIMEOUT))
@@ -193,27 +209,31 @@ _S_msg_report_wait (mach_port_t msgport, thread_t thread,
pure timeout. Report the timeout value (counted
in milliseconds); note this is the original total
time, not the time remaining. */
- strcpy (describe_number (description, 0, timeout), "ms");
+ cur = describe_number (cur, 0, timeout, limit - cur);
+ cur = __stpncpy (cur, "ms", limit - cur);
*msgid = 0;
}
else
{
- strcpy (description, "mach_msg");
+ cur = __stpncpy (cur, "mach_msg", limit - cur);
*msgid = 0;
}
}
else /* Some other system call. */
{
- (void) describe_number (description, "syscall#", *msgid);
+ cur = describe_number (cur, "syscall#", *msgid, limit - cur);
*msgid = 0;
}
}
- else
- description[0] = '\0';
}
}
__mach_port_deallocate (__mach_task_self (), thread);
+
+ if (cur == limit)
+ return ENOMEM;
+
+ *cur = '\0';
return 0;
}
@@ -232,7 +252,7 @@ _S_msg_describe_ports (mach_port_t msgport, mach_port_t refport,
while (nports-- > 0)
{
char this[200];
- describe_port (this, *ports++);
+ describe_port (this, *ports++, sizeof this);
p = __stpncpy (p, this, end - p);
if (p == end && p[-1] != '\0')
return ENOMEM;