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https://sourceware.org/git/glibc.git
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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.
This commit is contained in:
Samuel Thibault
parent
dba88fb3ed
commit
76ea70c613
@ -26,12 +26,16 @@
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#include <intr-msg.h>
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static char *
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describe_number (string_t description, const char *flavor, long int i)
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describe_number (char *description, const char *flavor, long int i, size_t size)
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{
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unsigned long int j;
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char *p = flavor == NULL ? description : __stpcpy (description, flavor);
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char *limit = description + size;
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char *p = flavor == NULL ? description : __stpncpy (description, flavor, size);
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char *end;
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if (p == limit)
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return p;
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/* Handle sign. */
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if (i < 0)
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{
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@ -39,15 +43,24 @@ describe_number (string_t description, const char *flavor, long int i)
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*p++ = '-';
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}
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if (p == limit)
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return p;
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/* Allocate space for the number at the end of DESCRIPTION. */
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for (j = i; j >= 10; j /= 10)
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p++;
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end = p + 1;
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*end = '\0';
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if (end < limit)
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*end = '\0';
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else
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end = limit;
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do
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{
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*p-- = '0' + i % 10;
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if (p < limit)
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*p = '0' + i % 10;
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p--;
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i /= 10;
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} while (i != 0);
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@ -55,27 +68,27 @@ describe_number (string_t description, const char *flavor, long int i)
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}
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static char *
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describe_port (string_t description, mach_port_t port)
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describe_port (char *description, mach_port_t port, size_t size)
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{
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int i;
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if (port == MACH_PORT_NULL)
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return __stpcpy (description, "(null)");
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return __stpncpy (description, "(null)", size);
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if (port == MACH_PORT_DEAD)
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return __stpcpy (description, "(dead)");
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return __stpncpy (description, "(dead)", size);
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if (port == __mach_task_self ())
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return __stpcpy (description, "task-self");
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return __stpncpy (description, "task-self", size);
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for (i = 0; i < _hurd_nports; ++i)
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if (port == _hurd_ports[i].port)
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return describe_number (description, "init#", i);
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return describe_number (description, "init#", i, size);
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if (_hurd_init_dtable)
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{
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for (i = 0; i < _hurd_init_dtablesize; ++i)
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if (port == _hurd_init_dtable[i])
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return describe_number (description, "fd#", i);
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return describe_number (description, "fd#", i, size);
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}
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if (_hurd_dtable)
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{
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@ -83,12 +96,12 @@ describe_port (string_t description, mach_port_t port)
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if (_hurd_dtable[i] == NULL)
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continue;
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else if (port == _hurd_dtable[i]->port.port)
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return describe_number (description, "fd#", i);
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return describe_number (description, "fd#", i, size);
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else if (port == _hurd_dtable[i]->ctty.port)
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return describe_number (description, "bgfd#", i);
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return describe_number (description, "bgfd#", i, size);
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}
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return describe_number (description, "port#", port);
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return describe_number (description, "port#", port, size);
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}
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@ -106,13 +119,15 @@ kern_return_t
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_S_msg_report_wait (mach_port_t msgport, thread_t thread,
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string_t description, mach_msg_id_t *msgid)
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{
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char *limit = description + 1024; /* XXX */
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char *cur = description;
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*msgid = 0;
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if (thread == _hurd_msgport_thread)
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/* Cute. */
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strcpy (description, "msgport");
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cur = __stpncpy (cur, "msgport", limit - cur);
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else if (&_hurd_itimer_thread && thread == _hurd_itimer_thread)
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strcpy (description, "itimer");
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cur = __stpncpy (cur, "itimer", limit - cur);
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else
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{
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/* Make sure this is really one of our threads. */
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@ -129,7 +144,7 @@ _S_msg_report_wait (mach_port_t msgport, thread_t thread,
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return EINVAL;
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if (ss->suspended != MACH_PORT_NULL)
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strcpy (description, "sigsuspend");
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cur = __stpncpy (cur, "sigsuspend", limit - cur);
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else
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{
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/* Examine the thread's state to see if it is blocked in an RPC. */
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@ -155,7 +170,6 @@ _S_msg_report_wait (mach_port_t msgport, thread_t thread,
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&& MSG_EXAMINE (&state, msgid, &rcv_port, &send_port,
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&option, &timeout) == 0)
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{
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char *p;
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if (send_port != MACH_PORT_NULL && *msgid != 0)
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{
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/* For the normal case of RPCs, we consider the
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@ -168,13 +182,14 @@ _S_msg_report_wait (mach_port_t msgport, thread_t thread,
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/* This is a Hurd interruptible RPC.
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Mark it by surrounding the port description
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string with [...] brackets. */
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description[0] = '[';
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p = describe_port (description + 1, send_port);
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*p++ = ']';
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*p = '\0';
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if (cur < limit)
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*cur++ = '[';
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cur = describe_port (cur, send_port, limit - cur);
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if (cur < limit)
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*cur++ = ']';
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}
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else
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(void) describe_port (description, send_port);
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cur = describe_port (cur, send_port, limit - cur);
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}
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else if (rcv_port != MACH_PORT_NULL)
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{
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@ -183,7 +198,8 @@ _S_msg_report_wait (mach_port_t msgport, thread_t thread,
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some garbage or perhaps the msgid of the last
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message this thread received, but it's not a
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helpful thing to return. */
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strcpy (describe_port (description, rcv_port), ":rcv");
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cur = describe_port (cur, rcv_port, limit - cur);
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cur = __stpncpy (cur, ":rcv", limit - cur);
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*msgid = 0;
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}
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else if ((option & (MACH_RCV_MSG|MACH_RCV_TIMEOUT))
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@ -193,27 +209,31 @@ _S_msg_report_wait (mach_port_t msgport, thread_t thread,
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pure timeout. Report the timeout value (counted
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in milliseconds); note this is the original total
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time, not the time remaining. */
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strcpy (describe_number (description, 0, timeout), "ms");
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cur = describe_number (cur, 0, timeout, limit - cur);
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cur = __stpncpy (cur, "ms", limit - cur);
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*msgid = 0;
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}
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else
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{
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strcpy (description, "mach_msg");
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cur = __stpncpy (cur, "mach_msg", limit - cur);
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*msgid = 0;
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}
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}
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else /* Some other system call. */
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{
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(void) describe_number (description, "syscall#", *msgid);
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cur = describe_number (cur, "syscall#", *msgid, limit - cur);
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*msgid = 0;
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}
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}
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else
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description[0] = '\0';
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}
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}
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__mach_port_deallocate (__mach_task_self (), thread);
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if (cur == limit)
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return ENOMEM;
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*cur = '\0';
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return 0;
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}
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@ -232,7 +252,7 @@ _S_msg_describe_ports (mach_port_t msgport, mach_port_t refport,
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while (nports-- > 0)
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{
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char this[200];
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describe_port (this, *ports++);
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describe_port (this, *ports++, sizeof this);
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p = __stpncpy (p, this, end - p);
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if (p == end && p[-1] != '\0')
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return ENOMEM;
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