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analogdevicesinc / libiio

A cross platform library for interfacing with local and remote Linux IIO devices
http://analogdevicesinc.github.io/libiio/
GNU Lesser General Public License v2.1
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SIG11 in comptibility API V1.0 #1140

Closed vvsvvsvvs closed 7 months ago

vvsvvsvvs commented 8 months ago

iio_device_attr_write_bool (compat.c) does not check the return from iio_device_find_attr(), that CAN be NULL if attr not found (it is 0, or NULL, not -1 as expected on error). Thus, if attr was not found for a dev, there is a SIG11 issue. So, it may be an issue for the whole API with functions returning a pointer.

pcercuei commented 8 months ago

You are right, the "attr_read" function does check the return from iio_device_find_attr, but the "attr_write" does not.

vvsvvsvvs commented 8 months ago

Running with Valgrind (current git version):

==390139== Command: ./iio-monitor
==390139==    
==390139== Invalid read of size 4
==390139==    at 0x486388B: iio_attr_find (attr.c:150)
==390139==    by 0x4867F08: iio_context_find_attr (context.c:511)
==390139==    by 0x4877421: dnssd_add_scan_result (dns_sd.c:115)
==390139==    by 0x4877DA0: dnssd_context_scan (dns_sd.c:309)
==390139==    by 0x4869C71: iio_scan (scan.c:122)
==390139==    by 0x10B3FB: show_contexts_screen (iio-monitor.c:263)
==390139==    by 0x10BCB1: main (iio-monitor.c:445)
==390139==  Address 0xffffffffffffffe9 is not stack'd, malloc'd or (recently) free'd

NOTE: sometimes code works well. URI: ip:192.168.0.24 Pluto.

pcercuei commented 8 months ago

The check after the iio_context_create is wrong, it's a pointer-encoded error - the check should actually be if (iio_err(ctx)) { ... }. The "ctx" pointer is therefore not valid and it cascades into the issue you pasted above.