pn532_uart.c:293:5: warning: Use of memory after it is freed
log_put(LOG_GROUP, LOG_CATEGORY, NFC_LOG_PRIORITY_ERROR, "pn53x_check_communication error on %s", ndd.port);
^ ~~~~~~~~
Calling ioctl flush too fast before actual garbage bytes arrive was useless.
It solves an issue e.g. when config asks for scanning for multiple incompatible serial devices:
One scan can mess up the reader and we've to wait & flush properly for the next driver to be able to scan correctly
Problem reported by Coverity:
CID 1090344 (#1 of 1): Use of untrusted string value (TAINTED_STRING)
. tainted_string: Passing tainted string "res->log_level" to "log_init(nfc_context const *)", which cannot accept tainted data.[show details]
Redundant result check leading to dead code was probably indicative
of a missing return value check of acr122_usb_send_apdu()
Problem reported by Coverity:
at_least: At condition "res < 0", the value of "res" must be at least 12.
cannot_single: At condition "res < 0", the value of "res" cannot be equal to -6.
dead_error_condition: The condition "res < 0" cannot be true.
CID 1090327 (#1 of 1): Logically dead code (DEADCODE)
dead_error_begin: Execution cannot reach this statement "acr122_usb_ack(pnd);".
Problem reported by Coverity:
CID 1090334 (#1 of 1): Big parameter passed by value (PASS_BY_VALUE)
pass_by_value: Passing parameter nt of type nfc_target const (size 291 bytes) by value.
Commit 54729fb458 removed some dead code spotted by Coverity
but it had as effect to trigger a gcc warning, which prefers to see all enum in a switch rather than dead code:
pn53x.c: In function 'pn53x_InJumpForDEP':
pn53x.c:2552:5: warning: enumeration value 'NBR_UNDEFINED' not handled in switch [-Wswitch]
pn53x.c:2552:5: warning: enumeration value 'NBR_847' not handled in switch [-Wswitch]
So both switches were merged, which slightly optimizes the code for speed.
Problem reported by Coverity:
CID 1090321 (#1 of 1): Unchecked return value (CHECKED_RETURN)
unchecked_value: No check of the return value of "pn53x_set_property_bool(pnd, NP_INFINITE_SELECT, true)".
Problem reported by Coverity:
CID 1090322 (#1 of 1): Unchecked return value (CHECKED_RETURN)
unchecked_value: No check of the return value of "pn53x_build_frame(abtFrame, &szFrame, pbtData, szData)".
Note that this could happen e.g. if a fake PN533 sends malicious frames over USB
CID 1090329 (#1 of 1): Overflowed return value (INTEGER_OVERFLOW)
overflow_sink: Overflowed or truncated value (or a value computed from an overflowed or truncated value) "res" used as return value.
Problem reported by Coverity:
at_most: At condition "io_res < 0", the value of "io_res" must be at most -1.
dead_error_condition: The condition "io_res < 0" must be true.
CID 1090328 (#1 of 1): Logically dead code (DEADCODE)
dead_error_line: Execution cannot reach this expression "0" inside statement "return (io_res < 0) ? io_re...".
Problem reported by Coverity:
dead_error_condition: The switch value "nbr" cannot be "NBR_UNDEFINED".
CID 1090326 (#1 of 2): Logically dead code (DEADCODE)
dead_error_begin: Execution cannot reach this statement "case NBR_UNDEFINED:".
This avoids Coverity being unhappy that only lower bound was defined, well I hope
lower_bounds: Checking lower bounds of signed scalar "waiting_time" by "waiting_time > 0".
CID 1090343 (#1 of 1): Untrusted value as argument (TAINTED_SCALAR)
tainted_data: Passing tainted variable "waiting_time" to a tainted sink.
sleep(waiting_time);
Problem reported by Coverity:
CID 1090323 (#1 of 1): Unchecked return value (CHECKED_RETURN)
unchecked_value: No check of the return value of "nfc_initiator_select_passive_target(pnd, nmMifare, nt.nti.nai.abtUid, nt.nti.nai.szUidLen, NULL)".
Problem reported by Coverity:
CID 1090325 (#1 of 1): Unchecked return value (CHECKED_RETURN)
unchecked_value: No check of the return value of "nfc_device_set_property_bool(pnd, NP_AUTO_ISO14443_4, false)".
Problem reported by Coverity:
CID 1090318 (#1 of 1): Truncated stdio return value (CHAR_IO)
char_io: Assigning the return value of "getchar(void)" to char "input" truncates its value
Hopefully fix TOCTOU by calling fopen() before stat()
At least this should prevent Coverity to complain about it:
CID 1090346 (#1 of 1): Time of check time of use (TOCTOU)
fs_check_call: Calling function "stat(char const *, struct stat *)" to perform check on "filename".
toctou: Calling function "fopen(char const * restrict, char const * restrict)" that uses "filename" after a check function. This can cause a time-of-check, time-of-use race condition.
Note that it seems pretty hard to avoid completely:
https://en.wikipedia.org/wiki/Time_of_check_to_time_of_use#Preventing_TOCTTOU
switch case was redundant as getopt was already telling the issue:
nfc-read-forum-tag3: option requires an argument -- 'o'
Option -o requires an argument.
This fixes also a problem reported by Coverity about missing break:
CID 1090330 (#1 of 1): Missing break in switch (MISSING_BREAK)
unterminated_case: This case (value 63) is not terminated by a 'break' statement.
Fix warning
uart.c:146:3: warning: ignoring return value of 'read', declared with attribute warn_unused_result [-Wunused-result]
Also reported by Coverity:
CID undefined (#1 of 1): Ignoring number of bytes read (CHECKED_RETURN)
check_return: "read(int, void *, size_t)" returns the number of bytes read, but it is ignored.
Problem reported by Coverity:
CID 1090340 (#1 of 2): Copy into fixed size buffer (STRING_OVERFLOW)
fixed_size_dest: You might overrun the 256 byte fixed-size string "context->user_defined_devices[context->user_defined_device_count - 1U].name" by copying "value" without checking the length.
parameter_as_source: Note: This defect has an elevated risk because the source argument is a parameter of the current function.
CID 1090340 (#2 of 2): Copy into fixed size buffer (STRING_OVERFLOW)[select issue]
Problem reported by Coverity:
CID 1091328 (#1 of 1): Out-of-bounds access (OVERRUN)
overrun-buffer-arg: Overrunning buffer pointed to by "&abtTxBuf[6]" of 271 bytes by passing it to a function which accesses it at byte offset 271 using argument "szData" (which evaluates to 266).
Problem reported by Coverity
CID 1090319 (#1 of 1): Unchecked return value (CHECKED_RETURN)
unchecked_value: No check of the return value of "nfc_device_set_property_bool(pnd, NP_EASY_FRAMING, nt.nti.nai.btSak & 0x20)".
CID 1090320 (#1 of 1): Unchecked return value (CHECKED_RETURN)
unchecked_value: No check of the return value of "nfc_device_set_property_bool(dev, NP_HANDLE_CRC, false)".
CID 1090324 (#1 of 2): Unchecked return value (CHECKED_RETURN)
unchecked_value: No check of the return value of "nfc_device_set_property_bool(pnd, NP_ACTIVATE_FIELD, true)".
CID 1090325 (#1 of 1): Unchecked return value (CHECKED_RETURN)
unchecked_value: No check of the return value of "nfc_device_set_property_bool(pnd, NP_AUTO_ISO14443_4, false)".
CID 1090331 (#1 of 1): Out-of-bounds access (OVERRUN)
11. overrun-buffer-arg: Overrunning array "pnti->nai.abtUid" of 10 bytes by passing it to a function which accesses it at byte offset 11 using argument "pnti->nai.szUidLen" (which evaluates to 12).
as Coverity fails seeing that szTargetTypes will always be = 0 in the case believed to lead to reading unitialized data in apttTargetTypes.
CID 1090347 (#1 of 1): Uninitialized scalar variable (UNINIT)
4. uninit_use_in_call: Using uninitialized element of array "apttTargetTypes" when calling "pn53x_InAutoPoll(struct nfc_device *, pn53x_target_type const *, size_t const, uint8_t const, uint8_t const, nfc_target *, int const)".
source could be larger than destination
Problem reported by Coverity
CID 1090342 (#1 of 1): Unbounded source buffer (STRING_SIZE)
10. string_size: Passing string "envvar" of unknown size to "strcpy(char * restrict, char const * restrict)", which expects a string of a particular size.
Problems reported by Coverity:
CID 1090335 (#1 of 1): Resource leak (RESOURCE_LEAK)
24. leaked_storage: Variable "acPorts" going out of scope leaks the storage it points to.
CID 1090336 (#1 of 1): Resource leak (RESOURCE_LEAK)
10. leaked_storage: Variable "acPorts" going out of scope leaks the storage it points to.
CID 1090337 (#1 of 1): Resource leak (RESOURCE_LEAK)
21. leaked_storage: Variable "i2cPorts" going out of scope leaks the storage it points to.
CID 1090338 (#1 of 1): Resource leak (RESOURCE_LEAK)
21. leaked_storage: Variable "acPorts" going out of scope leaks the storage it points to.
CID 1090339 (#1 of 1): Resource leak (RESOURCE_LEAK)
23. leaked_storage: Variable "acPorts" going out of scope leaks the storage it points to.
Actually the second part of the condition guaranteed that an out-of-bound read would never occur but now code is neater.
It was: for (j = 0; (j < "too_large_bound") && (const_ca[i].saklist[j] >= 0); j++)
Problem reported by Coverity
CID 1090332 (#1 of 1): Out-of-bounds read (OVERRUN)
67. overrun-local: Overrunning array "const_ca[i].saklist" of 8 4-byte elements at element index 31 (byte offset 124) using index "j" (which evaluates to 31).
A buffer overflow could occur is a triple-size UID card was read with a PN531.
Moreover the way cascade tags were removed was just wrong.
Problem reported by Coverity
CID 1090331 (#1 of 1): Out-of-bounds access (OVERRUN)
10. overrun-buffer-arg: Overrunning buffer pointed to by "&pnti->nai.abtUid[5]" of 10 bytes by passing it to a function which accesses it at byte offset 11 using argument "7UL".
Coverity reported a read out of bounds but actually the real problem if PN531 and triple-size UID will already occur at
memcpy(pnti->nai.abtUid, pbtRawData, pnti->nai.szUidLen); where abtUid is of size 10 and szUidLen of size 12
Philippe Teuwen