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Fix segfault for LDAP-authenticated users#860

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aaronokano wants to merge 1 commit intosharpbracket:masterfrom
aaronokano:fix-getpwuid-null-segfault
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Fix segfault for LDAP-authenticated users#860
aaronokano wants to merge 1 commit intosharpbracket:masterfrom
aaronokano:fix-getpwuid-null-segfault

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@aaronokano
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If a user is logged in via LDAP, some implementations of getpwuid() seem
to return NULL. Dereferencing this pointer will cause a segfault. This
change avoids dereferencing the potential NULL pointer.

If a user is logged in via LDAP, some implementations of getpwuid() seem
to return NULL. Dereferencing this pointer will cause a segfault. This
change avoids dereferencing the potential NULL pointer.
@rumpeltux
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Thanks for the patch! LGTM, I hope the owners can soon merge this.
This can also happen if the apparmor profile that comes with debian is enabled which doesn’t grant read access to /etc/passwd*.

rumpeltux added a commit to rumpeltux/redshift that referenced this pull request Apr 18, 2022
Related bugs:
 * https://bugzilla.suse.com/show_bug.cgi?id=1111906
 * https://bugs.debian.org/988068
 * sharpbracket#672
 * sharpbracket#860

src/config-ini.c still looks for $HOME/.config/redshift.conf which
fails to open because the apparmor profile doesn’t allow it.

src/config-ini.c also does this:
   struct passwd *pwd = getpwuid(getuid());
   char *home = pwd->pw_dir;

Since getpwuid doesn’t have access to /etc/passwd* it returns NULL,
causing a segmentation fault in the line thereafter.
This code is not triggered if a config is specified (e.g.
-c redshift.conf) or $HOME/.config/redshift.conf exists.
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2 participants