Add a Coccinelle file to identify the dereferences of NULL variables This semantic patch identifies when a variable is known to be NULL after a test, but it is still dereferenced later. Signed-off-by: Nicolas Palix <npalix@xxxxxxx> Signed-off-by: Julia Lawall <julia@xxxxxxx> --- scripts/coccinelle/deref_null.cocci | 293 +++++++++++++++++++++++++++++++++++ 1 files changed, 293 insertions(+), 0 deletions(-) create mode 100644 scripts/coccinelle/deref_null.cocci diff --git a/scripts/coccinelle/deref_null.cocci b/scripts/coccinelle/deref_null.cocci new file mode 100644 index 0000000..9969d76 --- /dev/null +++ b/scripts/coccinelle/deref_null.cocci @@ -0,0 +1,293 @@ +/// +/// A variable is dereference under a NULL test. +/// Even though it is know to be NULL. +/// +// Confidence: Moderate +// Copyright: (C) 2010 Nicolas Palix, DIKU. GPLv2. +// Copyright: (C) 2010 Julia Lawall, DIKU. GPLv2. +// Copyright: (C) 2010 Gilles Muller, INRIA/LiP6. GPLv2. +// URL: http://coccinelle.lip6.fr/ +// Comments: -I ... -all_includes can give more complete results +// Options: + +virtual context +virtual patch +virtual org +virtual report + +@initialize:python depends on !context && patch && !org && !report@ + +import sys +print >> sys.stderr, "This semantic patch does not support the 'patch' mode." + +@depends on patch@ +@@ + +this_rule_should_never_matches(); + +@ifm depends on !patch@ +expression *E; +statement S1,S2; +position p1; +@@ + +if@p1 ((E == NULL && ...) || ...) S1 else S2 + +// The following two rules are separate, because both can match a single +// expression in different ways +@pr1 depends on !patch expression@ +expression *ifm.E; +identifier f; +position p1; +@@ + + (E != NULL && ...) ? <+...E->f@xxxxx+> : ... + +@pr2 depends on !patch expression@ +expression *ifm.E; +identifier f; +position p2; +@@ + +( + (E != NULL) && ... && <+...E->f@xxxxx+> +| + (E == NULL) || ... || <+...E->f@xxxxx+> +| + sizeof(<+...E->f@xxxxx+>) +) + +// For org and report modes + +@r depends on !context && !patch && (org || report) exists@ +expression subE <= ifm.E; +expression *ifm.E; +expression E1,E2; +identifier f; +statement S1,S2,S3,S4; +iterator iter; +position p!={pr1.p1,pr2.p2}; +position ifm.p1; +@@ + +if@p1 ((E == NULL && ...) || ...) +{ + ... when != if (...) S1 else S2 +( + iter(subE,...) S4 // no use +| + list_remove_head(E2,subE,...) +| + subE = E1 +| + for(subE = E1;...;...) S4 +| + subE++ +| + ++subE +| + --subE +| + subE-- +| + &subE +| + E->f@p // bad use +) + ... when any + return ...; +} +else S3 + +@script:python depends on !context && !patch && !org && report@ +p << r.p; +p1 << ifm.p1; +x << ifm.E; +@@ + +msg="ERROR: %s is NULL but dereferenced." % (x) +coccilib.report.print_report(p[0], msg) +cocci.include_match(False) + +@script:python depends on !context && !patch && org && !report@ +p << r.p; +p1 << ifm.p1; +x << ifm.E; +@@ + +msg="ERROR: %s is NULL but dereferenced." % (x) +msg_safe=msg.replace("[","@(").replace("]",")") +cocci.print_main(msg_safe,p) +cocci.include_match(False) + +@s depends on !context && !patch && (org || report) exists@ +expression subE <= ifm.E; +expression *ifm.E; +expression E1,E2; +identifier f; +statement S1,S2,S3,S4; +iterator iter; +position p!={pr1.p1,pr2.p2}; +position ifm.p1; +@@ + +if@p1 ((E == NULL && ...) || ...) +{ + ... when != if (...) S1 else S2 +( + iter(subE,...) S4 // no use +| + list_remove_head(E2,subE,...) +| + subE = E1 +| + for(subE = E1;...;...) S4 +| + subE++ +| + ++subE +| + --subE +| + subE-- +| + &subE +| + E->f@p // bad use +) + ... when any +} +else S3 + +@script:python depends on !context && !patch && !org && report@ +p << s.p; +p1 << ifm.p1; +x << ifm.E; +@@ + +msg="ERROR: %s is NULL but dereferenced." % (x) +coccilib.report.print_report(p[0], msg) + +@script:python depends on !context && !patch && org && !report@ +p << s.p; +p1 << ifm.p1; +x << ifm.E; +@@ + +msg="ERROR: %s is NULL but dereferenced." % (x) +msg_safe=msg.replace("[","@(").replace("]",")") +cocci.print_main(msg_safe,p) + +// For context mode + +@depends on context && !patch && !org && !report exists@ +expression subE <= ifm.E; +expression *ifm.E; +expression E1,E2; +identifier f; +statement S1,S2,S3,S4; +iterator iter; +position p!={pr1.p1,pr2.p2}; +position ifm.p1; +@@ + +if@p1 ((E == NULL && ...) || ...) +{ + ... when != if (...) S1 else S2 +( + iter(subE,...) S4 // no use +| + list_remove_head(E2,subE,...) +| + subE = E1 +| + for(subE = E1;...;...) S4 +| + subE++ +| + ++subE +| + --subE +| + subE-- +| + &subE +| +* E->f@p // bad use +) + ... when any + return ...; +} +else S3 + +// The following three rules are duplicates of ifm, pr1 and pr2 respectively. +// It is need because the previous rule as already made a "change". + +@ifm1 depends on !patch@ +expression *E; +statement S1,S2; +position p1; +@@ + +if@p1 ((E == NULL && ...) || ...) S1 else S2 + +@pr11 depends on !patch expression@ +expression *ifm1.E; +identifier f; +position p1; +@@ + + (E != NULL && ...) ? <+...E->f@xxxxx+> : ... + +@pr12 depends on !patch expression@ +expression *ifm1.E; +identifier f; +position p2; +@@ + +( + (E != NULL) && ... && <+...E->f@xxxxx+> +| + (E == NULL) || ... || <+...E->f@xxxxx+> +| + sizeof(<+...E->f@xxxxx+>) +) + +@depends on context && !patch && !org && !report exists@ +expression subE <= ifm1.E; +expression *ifm1.E; +expression E1,E2; +identifier f; +statement S1,S2,S3,S4; +iterator iter; +position p!={pr11.p1,pr12.p2}; +position ifm1.p1; +@@ + +if@p1 ((E == NULL && ...) || ...) +{ + ... when != if (...) S1 else S2 +( + iter(subE,...) S4 // no use +| + list_remove_head(E2,subE,...) +| + subE = E1 +| + for(subE = E1;...;...) S4 +| + subE++ +| + ++subE +| + --subE +| + subE-- +| + &subE +| +* E->f@p // bad use +) + ... when any +} +else S3 -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
